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  • 1.
    ., .
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    FIRE RISK MANAGEMENT PROCEDURE FOR VEHICLES AND MOBILE MACHINES2019Other (Other academic)
    Abstract [en]

    The method described in this document introduces a procedure for management of fire hazards in vehicles and mobile machines. The method particularly provides elaborate support for identification of fire hazards in newly assembled vehicles and mobile machines as well as fire hazards resulting from operation, maintenance and retrofitting. The method presents how the identified hazards can be translated to estimations of fire risks and how these can be evaluated. Recommendations are also given on fire risk reduction measures for common designs, procedures and systems. This method is based on experience and knowledge gained through research, fire investigations and other industry professional services, as well as information provided by the industry. The method does not guarantee elimination of fires but regularly performed fire risk management will promote fire safety.

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    fulltext
  • 2.
    ., .
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    FIRE SAFETY IN ENGINE COMPARTMENTS: SP Method 4912: Testing of fire suppression system intended for use in compartment with combustion engine.2019Other (Other academic)
    Abstract [en]

    This method assesses the fire suppression performance of fire suppression systems under mock-up operational conditions. For this purpose, several different types of fires are ignited and stabilised inside an enclosure with typical engine compartment characteristics before the fire suppression system is activated. After the fire suppression system has been activated and completely discharged, the system is evaluated based on its ability to extinguish various fire sources.

    In order to ensure the reproducibility of the test and facilitate its adoption in different laboratories, the method utilizes a standardised mock-up.

    The fire suppression system is evaluated both as a complete system and in terms of components.

    Durability tests are adapted for harsh vehicle conditions and are adjusted to suit both on-road applications as well as off-road applications.

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    fulltext
  • 3.
    -, -
    RISE - Research Institutes of Sweden.
    SP Method 2369: Protection System for Storage of Inflammable Goods in Retail Environments - Fire Safety Cabinets2018Other (Other academic)
    Abstract [en]

    This method evaluates the construction of fire safety cabinets designated for storing flammable goods in retail environments and their ability to internal and external fires. The general function of this cabinet must show that it controls and extinguishes a large internal fire, but also that an external fire does not spread to its flammable contents.

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    SP Method 2369
  • 4.
    -, -
    RISE - Research Institutes of Sweden, Safety and Transport.
    SP Metod 2369: Skyddssystem för förvaring av brandfarlig vara på försäljningstlännen - Brandavskiljande skåp2018Other (Other academic)
    Abstract [sv]

    Försäljning av produkter som är klassade som brandfarlig vara förekommer på många olika typer av försäljningsställen, från små butiker till stora varuhus och stormarknader. Som förpackningsmaterial förekommer ofta plast och försök har visat att detta ur brandsynpunkt kan leda till en allvarlig situation på grund av en mycket snabb brandspridning (bl a SP Rapport 2007:24). Dåvarande sprängämnesinspektionen utarbetade därför föreskrifter, SÄIFS 1996:2

    1, som reglerade hanteringen av brandfarliga gaser och vätskor på försäljningsställen. I föreskrifterna krävdes bl a att "Brandfarlig gas och vätska skall hanteras på sådant sätt att betryggande säkerhet föreligger. Hanteringen får inte försvåra utrymning och räddningsinsats."

    I tillhörande "Allmänna råd" gavs exempel på de mängder av brandfarlig vara som kan anses acceptabel i olika lokaler samt avstånd till andra varor. Både mängd och avståndskrav innebar dock avsevärda begränsningar för handeln och föreskrifterna medgav därför att dessa skulle kunna ändras under förutsättning att åtgärder vidtogs för att upprätthålla avsedd säkerhetsnivå. Som exempel på sådana åtgärder omnämns möjligheten att förvara de brandfarliga varorna i ett eget utrymme eller i speciella brandavskiljande skåp.

    För att kunna utvärdera brandavskiljande skåp utvecklades SP Metod 2369.

    1

    I SP Metod 2369 beskrivs de provningsförfaranden och krav som kan tillämpas för att utvärdera skyddssystem i form av fristående skåp. Metodik och krav är baserade på erfarenheter och försök med brandfarlig vara enligt SP-Arbetsrapport 1997:35 vilka sedan fastställts efter samråd med en referensgrupp bestående av intressenter för myndigheter, räddningstjänst, handeln, försäkringsbolag samt tillverkare av skyddssystem.

    I MSB:s (Myndigheten för Samhällsskydd och Beredskap) arbete, 2016-2018, med att ta fram "Handbok Brandfarliga gaser och vätskor i butik" sågs ett behov av att kunna tillåta samförvaring av både brandfarliga gaser och vätskor i framtiden. Eftersom skåp tidigare varit avsedda för och utvärderats för förvaring av antingen brandfarlig gas eller brandfarlig vätska bedömdes det nödvändigt att förändra den tidigare kravbilden. Därmed uppstod ett behov av att förändra brandproven samt de allmänna konstruktions- och funktionskraven i SP Metod 2369 för att säkerställa att metoden överrensstämmer med de nya riktlinjerna från MSB.

    I arbetet inför version 6 av SP Metod 2369 genomfördes, som följd av MSB:s arbete med nya riktlinjer, försök med förlängd brandexponeringstid vid provet för utvändig brandpåverkan. Arbetet i SP-arbetsrapport 1997:35 kompletterades också med brandförsök gjorda för att undersöka vid vilken temperatur aerosolburkar exploderar. Resultaten av proven har bidragit till förändringen av provningsmetodik och krav vad gäller utvändig brandpåverkan gentemot SP Metod 2369 version 5 och tidigare.

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    SP Metod 2369
  • 5.
    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. 

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    fulltext
  • 6.
    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 (2017-2019), Bioeconomy, PFI.
    Syverud, Kristin
    RISE - Research Institutes of Sweden (2017-2019), 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, E-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.

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    fulltext
  • 7.
    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, E-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.

  • 8.
    Aaen, Ragnhild
    et al.
    Norwegian University of Science and Technology, Norway.
    Brodin, Fredrik Wernersson
    RISE - Research Institutes of Sweden (2017-2019), Bioeconomy, PFI.
    Simon, Sébastien
    Norwegian University of Science and Technology, Norway.
    Heggset, Ellinor B
    RISE - Research Institutes of Sweden (2017-2019), Bioeconomy, PFI.
    Syverud, Kristin
    RISE - Research Institutes of Sweden (2017-2019), 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, E-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.

  • 9.
    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, 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.].

  • 10.
    Aalberg, Asbjørn Lein
    et al.
    SINTEF, Norway.
    Aamodt, Edvard
    RISE Research Institutes of Sweden, Safety and Transport, Fire and Safety.
    Steen-Hansen, Anne
    RISE Research Institutes of Sweden, Safety and Transport, Fire and Safety.
    Holen, Siri Mariane
    SINTEF, Norway.
    Læring etter branner i Norge – forutsetninger, barrierer og fremmende faktorer2022Report (Other academic)
    Abstract [en]

    Denne rapporten presenterer resultater fra et prosjekt som er utført av Fire Research and Innovation Centre - FRIC fra 2020 til 2022. Første versjon av rapporten ble publisert på engelsk i mars 2022. Denne norske versjonen er oversatt av SINTEF Digital og RISE Fire Research i samarbeid. En spesiell takk til Caroline Kristensen for arbeidet med oversettelsen. Rapporten er også oppdatert på enkelte punkter, uten at fokus og konklusjoner skal være endret.

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    fulltext
  • 11.
    Aalberg, Asbjørn Lein
    et al.
    SINTEF Digital, Norway.
    Holen, Siri Mariane
    SINTEF Digital, Norway.
    Aamodt, Edvard
    RISE Research Institutes of Sweden, Safety and Transport, Fire and Safety.
    Steen-Hansen, Anne Elise
    RISE Research Institutes of Sweden, Safety and Transport, Fire and Safety. NTNU Norwegian University of Science and Technology, Norway.
    Preconditions for Learning from Fires in Norway: Structural, Cultural, Technological, Interactional and Relational Aspects2021In: Proceedings of the 31st European Safety and Reliability Conference, 2021, p. 1747-1754Conference paper (Refereed)
    Abstract [en]

    Learning from incidents is widely accepted as a core part of safety management. This is also true for fires – however few fires in Norway are investigated. Fires are interesting incidents conceptually due to their potential of devastating outcomes on material and human lives and because they happen across all sectors and industries, businesses, and homes. In Norway, several different actors play a role in investigating and learning from fires, from the fire rescue services to directorates and Non-Governmental Organisations. The present study seeks to understand the preconditions for learning from fires in Norway, with emphasis on the formal actors that play a role in preventing and mitigating fires. Methodologically, the study is based on qualitative interviews conducted with relevant actors from first responders, authorities, and other sectors. We found that there are structural, cultural, technological, and relational aspects that seem to influence learning from fires in Norway. The results were analyzed using thematic analysis and the Pentagon model framework. The findings are discussed in relation to theories from organisational learning and learning from incidents.

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    fulltext
  • 12.
    Abbas, Muhammad
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems.
    Requirements-Level Reuse Recommendation and Prioritization of Product Line Assets2021Other (Other academic)
    Abstract [en]

    Software systems often target a variety of different market segments. Targeting varying customer requirements requires a product-focused development process. Software Product Line (SPL) engineering is one possible approach based on reuse rationale to aid quick delivery of quality product variants at scale. SPLs reuse common features across derived products while still providing varying configuration options. The common features, in most cases, are realized by reusable assets. In practice, the assets are reused in a clone-and-own manner to reduce the upfront cost of systematic reuse. Besides, the assets are implemented in increments, and requirements prioritization also has to be done. In this context, the manual reuse analysis and prioritization process become impractical when the number of derived products grows. Besides, the manual reuse analysis process is time-consuming and heavily dependent on the experience of engineers. In this licentiate thesis, we study requirements-level reuse recommendation and prioritization for SPL assets in industrial settings. We first identify challenges and opportunities in SPLs where reuse is done in a clone-and-own manner. We then focus on one of the identified challenges: requirements-based SPL assets reuse and provide automated support for identifying reuse opportunities for SPL assets based on requirements. Finally, we provide automated support for requirements prioritization in the presence of dependencies resulting from reuse.

  • 13.
    Abbas, Muhammad
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems.
    Variability aware requirements reuse analysis2020In: Proceedings - International Conference on Software Engineering, IEEE Computer Society , 2020, p. 190-193Conference paper (Refereed)
    Abstract [en]

    Problem: The goal of a software product line is to aid quick andquality delivery of software products, sharing common features.Effectively achieving the above-mentioned goals requires reuseanalysis of the product line features. Existing requirements reuseanalysis approaches are not focused on recommending product linefeatures, that can be reused to realize new customer requirements.Hypothesis: Given that the customer requirements are linked toproduct line features' description satisfying them: then the customer requirements can be clustered based on patterns and similarities, preserving the historic reuse information. New customerrequirements can be evaluated against existing customer requirements and reuse of product line features can be recommended.Contributions: We treated the problem of feature reuse analysisas a text classification problem at the requirements-level. We useNatural Language Processing and clustering to recommend reuseof features based on similarities and historic reuse information.The recommendations can be used to realize new customer requirements. © 2020 Copyright held by the owner/author(s).

  • 14.
    Abbas, Muhammad
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems. Mälardalens University, Sweden.
    Ferrari, Alessio
    CNR-ISTI, Italy.
    Shatnawi, Anas
    Berget-Levrault, France.
    Enoiu, Eduard
    Mälardalens University, Sweden.
    Saadatmand, Mehrdad
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems.
    Is Requirements Similarity a Good Proxy for Software Similarity?: An Empirical Investigation in Industry2021In: Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) 27th International Working Conference on Requirements Engineering: Foundation for Software Quality, REFSQ 2021, 12 April 2021 - 15 April 2021, Springer Science and Business Media Deutschland GmbH , 2021, Vol. 12685, p. 3-18Conference paper (Refereed)
    Abstract [en]

    [Context and Motivation] Content-based recommender systems for requirements are typically built on the assumption that similar requirements can be used as proxies to retrieve similar software. When a new requirement is proposed by a stakeholder, natural language processing (NLP)-based similarity metrics can be exploited to retrieve existing requirements, and in turn identify previously developed code. [Question/problem] Several NLP approaches for similarity computation are available, and there is little empirical evidence on the adoption of an effective technique in recommender systems specifically oriented to requirements-based code reuse. [Principal ideas/results] This study compares different state-of-the-art NLP approaches and correlates the similarity among requirements with the similarity of their source code. The evaluation is conducted on real-world requirements from two industrial projects in the railway domain. Results show that requirements similarity computed with the traditional tf-idf approach has the highest correlation with the actual software similarity in the considered context. Furthermore, results indicate a moderate positive correlation with Spearman’s rank correlation coefficient of more than 0.5. [Contribution] Our work is among the first ones to explore the relationship between requirements similarity and software similarity. In addition, we also identify a suitable approach for computing requirements similarity that reflects software similarity well in an industrial context. This can be useful not only in recommender systems but also in other requirements engineering tasks in which similarity computation is relevant, such as tracing and categorization.

  • 15.
    Abbas, Muhammad
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems.
    Ferrari, Alessio
    CNR-ISTI, Italy.
    Shatnawi, Anas
    Berger-Levrault, France.
    Enoiu, Eduard
    Mälardalen University, Sweden.
    Saadatmand, Mehrdad
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems.
    Sundmark, Daniel
    Mälardalen University, Sweden.
    On the relationship between similar requirements and similar software: A case study in the railway domain2023In: Requirements Engineering, ISSN 0947-3602, E-ISSN 1432-010X, Vol. 28, p. 23-47Article in journal (Refereed)
    Abstract [en]

    Recommender systems for requirements are typically built on the assumption that similar requirements can be used as proxies to retrieve similar software. When a stakeholder proposes a new requirement, natural language processing (NLP)-based similarity metrics can be exploited to retrieve existing requirements, and in turn, identify previously developed code. Several NLP approaches for similarity computation between requirements are available. However, there is little empirical evidence on their effectiveness for code retrieval. This study compares different NLP approaches, from lexical ones to semantic, deep-learning techniques, and correlates the similarity among requirements with the similarity of their associated software. The evaluation is conducted on real-world requirements from two industrial projects from a railway company. Specifically, the most similar pairs of requirements across two industrial projects are automatically identified using six language models. Then, the trace links between requirements and software are used to identify the software pairs associated with each requirements pair. The software similarity between pairs is then automatically computed with JPLag. Finally, the correlation between requirements similarity and software similarity is evaluated to see which language model shows the highest correlation and is thus more appropriate for code retrieval. In addition, we perform a focus group with members of the company to collect qualitative data. Results show a moderately positive correlation between requirements similarity and software similarity, with the pre-trained deep learning-based BERT language model with preprocessing outperforming the other models. Practitioners confirm that requirements similarity is generally regarded as a proxy for software similarity. However, they also highlight that additional aspect comes into play when deciding software reuse, e.g., domain/project knowledge, information coming from test cases, and trace links. Our work is among the first ones to explore the relationship between requirements and software similarity from a quantitative and qualitative standpoint. This can be useful not only in recommender systems but also in other requirements engineering tasks in which similarity computation is relevant, such as tracing and change impact analysis.

  • 16.
    Abbas, Muhammad
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems. Mälardalens University, Sweden.
    Hamayouni, Ali
    Mälardalens University, Sweden.
    Helali Moghadam, Mahshid
    RISE Research Institutes of Sweden.
    Saadatmand, Mehrdad
    RISE Research Institutes of Sweden.
    Strandberg, Per Erik
    Westermo Network Technologies AB, Sweden.
    Making Sense of Failure Logs in an Industrial DevOps Environment2023In: Advances in Intelligent Systems and Computing book series (AISC,volume 1445): 20th International Conference on Information Technology New Generations, Springer International Publishing , 2023, Vol. 1445, p. 217-226Conference paper (Refereed)
    Abstract [en]

    Processing and reviewing nightly test execution failure logs for large industrial systems is a tedious activity. Furthermore, multiple failures might share one root/common cause during test execution sessions, and the review might therefore require redundant efforts. This paper presents the LogGrouper approach for automated grouping of failure logs to aid root/common cause analysis and for enabling the processing of each log group as a batch. LogGrouper uses state-of-art natural language processing and clustering approaches to achieve meaningful log grouping. The approach is evaluated in an industrial setting in both a qualitative and quantitative manner. Results show that LogGrouper produces good quality groupings in terms of our two evaluation metrics (Silhouette Coefficient and Calinski-Harabasz Index) for clustering quality. The qualitative evaluation shows that experts perceive the groups as useful, and the groups are seen as an initial pointer for root cause analysis and failure assignment.

  • 17.
    Abbas, Muhammad
    et al.
    RISE - Research Institutes of Sweden (2017-2019), ICT, SICS.
    Inayat, I.
    National University of Computer and Emerging Sciences, Pakistan.
    Jan, N.
    National University of Computer and Emerging Sciences, Pakistan.
    Saadatmand, Mehrdad
    RISE - Research Institutes of Sweden (2017-2019), ICT, SICS.
    Enoiu, E. Paul
    Mälardalen University, Sweden.
    Sundmark, D.
    Mälardalen University, Sweden.
    MBRP: Model-Based Requirements Prioritization Using PageRank Algorithm2019In: 2019 26th Asia-Pacific Software Engineering Conference (APSEC), 2019, p. 31-38Conference paper (Refereed)
    Abstract [en]

    Requirements prioritization plays an important role in driving project success during software development. Literature reveals that existing requirements prioritization approaches ignore vital factors such as interdependency between requirements. Existing requirements prioritization approaches are also generally time-consuming and involve substantial manual effort. Besides, these approaches show substantial limitations in terms of the number of requirements under consideration. There is some evidence suggesting that models could have a useful role in the analysis of requirements interdependency and their visualization, contributing towards the improvement of the overall requirements prioritization process. However, to date, just a handful of studies are focused on model-based strategies for requirements prioritization, considering only conflict-free functional requirements. This paper uses a meta-model-based approach to help the requirements analyst to model the requirements, stakeholders, and inter-dependencies between requirements. The model instance is then processed by our modified PageRank algorithm to prioritize the given requirements. An experiment was conducted, comparing our modified PageRank algorithm's efficiency and accuracy with five existing requirements prioritization methods. Besides, we also compared our results with a baseline prioritized list of 104 requirements prepared by 28 graduate students. Our results show that our modified PageRank algorithm was able to prioritize the requirements more effectively and efficiently than the other prioritization methods.

  • 18.
    Abbas, Muhammad
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems.
    Inayat, Irum
    National University of Computer& Emerging Sciences, Pakistan.
    Jan, Naila
    National University of Computer& Emerging Sciences, Pakistan.
    Saadatmand, Mehrdad
    RISE Research Institutes of Sweden.
    Enoiu, Eduard Paul
    Mälardalen University, Sweden.
    Sundmark, Daniel
    Mälardalen University, Sweden.
    MBRP: Model-based Requirements Prioritization Using PageRank Algorithm2019In: The 26th Asia-Pacific Software Engineering Conference, IEEE conference proceedings, 2019Conference paper (Refereed)
    Abstract [en]

    Requirements prioritization plays an important role in driving project success during software development. Literature reveals that existing requirements prioritization approaches ignore vital factors such as interdependency between requirements. Existing requirements prioritization approaches are also generally time-consuming and involve substantial manual effort. Besides, these approaches show substantial limitations in terms of the number of requirements under consideration. There is some evidence suggesting that models could have a useful role in the analysis of requirements interdependency and their visualization, contributing towards the improvement of the overall requirements prioritization process. However, to date, just a handful of studies are focused on model-based strategies for requirements prioritization, considering only conflict-free functional requirements. This paper uses a meta-model-based approach to help the requirements analyst to model the requirements, stakeholders, and inter-dependencies between requirements. The model instance is then processed by our modified PageRank algorithm to prioritize the given requirements. An experiment was conducted, comparing our modified PageRank algorithm’s efficiency and accuracy with five existing requirements prioritization methods. Besides, we also compared our results with a baseline prioritized list of 104 requirements prepared by 28 graduate students. Our results show that our modified PageRank algorithm was able to prioritize the requirements more effectively and efficiently than the other prioritization methods.

  • 19.
    Abbas, Muhammad
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems.
    Inayat, Irum
    National University of Computer & Emerging Sciences, Pakistan.
    Saadatmand, Mehrdad
    RISE Research Institutes of Sweden.
    Jan, Naila
    National University of Computer & Emerging Sciences, Pakistan.
    Requirements dependencies-based test case prioritization for extra-functional properties2019In: IEEE International Conference on Software Testing, Verification and Validation Workshops, IEEE , 2019Conference 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.

  • 20.
    Abbas, Muhammad
    et al.
    RISE - Research Institutes of Sweden (2017-2019), ICT, SICS.
    Inayat, Irum
    National University of Computer & Emerging Sciences, Pakistan.
    Saadatmand, Mehrdad
    RISE - Research Institutes of Sweden (2017-2019), 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.

  • 21.
    Abbas, Muhammad
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems.
    Jongeling, Robbert
    Mälardalen University, Sweden.
    Lindskog, Claes
    Bombardier Transportation AB, Sweden.
    Enoiu, Eduard
    Mälardalen University, Sweden.
    Saadatmand, Mehrdad
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems.
    Sundmark, Daniel
    Mälardalen University, Sweden.
    Product line adoption in industry: an experience report from the railway domain2020In: SPLC '20: Proceedings of the 24th ACM Conference on Systems and Software Product Line: Volume A, Association for Computing Machinery , 2020, p. 130-141, article id 3Conference paper (Refereed)
    Abstract [en]

    The software system controlling a train is typically deployed on various hardware architectures and must process various signals across those deployments. The increase of such customization scenarios and the needed adherence of the software to various safety standards in different application domains has led to the adoption of product line engineering within the railway domain. This paper explores the current state-of-practice of software product line development within a team developing industrial embedded software for a train propulsion control system. Evidence is collected using a focus group session with several engineers and through inspection of archival data. We report several benefits and challenges experienced during product line adoption and deployment. Furthermore, we identify and discuss improvement opportunities, focusing mainly on product line evolution and test automation. 

  • 22.
    Abbas, Muhammad
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems.
    Rauf, Abdel
    RISE Research Institutes of Sweden.
    Saadatmand, Mehrdad
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems.
    Enoiu, Eduard
    Mälardalen University, Sweden.
    Sundmark, Daniel
    Mälardalen University, Sweden.
    Keywords-based test categorization for Extra-Functional Properties2020In: 2020 IEEE International Conference on Software Testing, Verification and Validation Workshops (ICSTW), 2020, p. 153-156Conference paper (Refereed)
    Abstract [en]

    Categorizing existing test specifications can provide insights on coverage of the test suite to extra-functional properties. Manual approaches for test categorization can be time-consuming and prone to error. In this short paper, we propose a semi-automated approach for semantic keywords-based textual test categorization for extra-functional properties. The approach is the first step towards coverage-based test case selection based on extra-functional properties. We report a preliminary evaluation of industrial data for test categorization for safety aspects. Results show that keyword-based approaches can be used to categorize tests for extra-functional properties and can be improved by considering contextual information of keywords.

  • 23.
    Abbas, Muhammad
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems.
    Saadatmand, Mehrdad
    RISE Research Institutes of Sweden.
    Enoiu, Eduard Paul
    Mälardalens University, Sweden.
    Requirements-driven Reuse Recommendation2021In: 25th ACM International Systems and Software Product Line Conference, ACM , 2021, Vol. AConference paper (Refereed)
    Abstract [en]

    This tutorial explores requirements-based reuse recommendation for product line assets in the context of clone-and-own product lines.

  • 24.
    Abbas, Muhammad
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems. Mälardalens University, Sweden.
    Saadatmand, Mehrdad
    RISE Research Institutes of Sweden.
    Enoiu, Eduard Paul
    Mälardalens University, Sweden.
    Sundmark, Daniel
    Mälardalens University, Sweden.
    Lindskog, Claes
    Bombardier Transportation AB, Sweden.
    Automated Reuse Recommendation of Product Line Assets based on Natural Language Requirements2020In: Reuse in Emerging Software Engineering Practices, Springer International Publishing , 2020, Vol. 12541, p. 173-189Conference paper (Refereed)
    Abstract [en]

    Software product lines (SPLs) are based on reuse rationale to aid quick and quality delivery of complex products at scale. Deriving a new product from a product line requires reuse analysis to avoid redundancy and support a high degree of assets reuse. In this paper, we propose and evaluate automated support for recommending SPL assets that can be reused to realize new customer requirements. Using the existing customer requirements as input, the approach applies natural language processing and clustering to generate reuse recommendations for unseen customer requirements in new projects. The approach is evaluated both quantitatively and qualitatively in the railway industry. Results show that our approach can recommend reuse with 74% accuracy and 57.4% exact match. The evaluation further indicates that the recommendations are relevant to engineers and can support the product derivation and feasibility analysis phase of the projects. The results encourage further study on automated reuse analysis on other levels of abstractions.

  • 25.
    Abbas, Muhammad
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems. Mälardalen University, Sweden.
    Saadatmand, Mehrdad
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems.
    Enoiu, Eduard
    Mälardalen University, Sweden.
    Sundamark, Daniel
    Mälardalen University, Sweden.
    Lindskog, Claes
    Bombardier Transportation AB, Sweden.
    Automated Reuse Recommendation of Product Line Assets Based on Natural Language Requirements2020In: Lecture Notes in Computer Science, Springer Science and Business Media Deutschland GmbH , 2020, Vol. 12541, p. 173-189Conference paper (Refereed)
    Abstract [en]

    Software product lines (SPLs) are based on reuse rationale to aid quick and quality delivery of complex products at scale. Deriving a new product from a product line requires reuse analysis to avoid redundancy and support a high degree of assets reuse. In this paper, we propose and evaluate automated support for recommending SPL assets that can be reused to realize new customer requirements. Using the existing customer requirements as input, the approach applies natural language processing and clustering to generate reuse recommendations for unseen customer requirements in new projects. The approach is evaluated both quantitatively and qualitatively in the railway industry. Results show that our approach can recommend reuse with 74% accuracy and 57.4% exact match. The evaluation further indicates that the recommendations are relevant to engineers and can support the product derivation and feasibility analysis phase of the projects. The results encourage further study on automated reuse analysis on other levels of abstractions. 

  • 26.
    Abbas, Nadeem
    et al.
    Linnaeus University, Sweden.
    Andersson, Jesper
    Linnaeus University, Sweden.
    Architectural Reasoning Support for Product-Lines of Self-adaptive Software Systems - A Case Study2015In: Software Architecture: 9th European Conference, ECSA 2015, Dubrovnik/Cavtat, Croatia, September 7-11, 2015. Proceedings, Springer International Publishing , 2015, 17, p. 20-36Chapter in book (Refereed)
    Abstract [en]

    Software architecture serves as a foundation for the design and development of software systems. Designing an architecture requires extensive analysis and reasoning. The study presented herein focuses on the architectural analysis and reasoning in support of engineering self-adaptive software systems with systematic reuse. Designing self-adaptive software systems with systematic reuse introduces variability along three dimensions; adding more complexity to the architectural analysis and reasoning process. To this end, the study presents an extended Architectural Reasoning Framework with dedicated reasoning support for self-adaptive systems and reuse. To evaluate the proposed framework, we conducted an initial feasibility case study, which concludes that the proposed framework assists the domain architects to increase reusability, reduce fault density, and eliminate differences in skills and experiences among architects, which were our research goals and are decisive factors for a system’s overall quality.

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  • 27.
    Abbas, Nadeem
    et al.
    Linnaeus University, Sweden.
    Andersson, Jesper
    Linnaeus University, Sweden.
    Harnessing Variability in Product-lines of Self-adaptive Software Systems2015In: Proceedings of the 19th International Conference on Software Product Line (SPLC '15), New York, NY, USA: Association for Computing Machinery (ACM), 2015, 12, p. 191-200Conference paper (Refereed)
    Abstract [en]

    This work studies systematic reuse in the context of self-adaptive software systems. In our work, we realized that managing variability for such platforms is different compared to traditional platforms, primarily due to the run-time variability and system uncertainties. Motivated by the fact that recent trends show that self-adaptation will be used more often in future system generation and that software reuse state-of-practice or research do not provide sufficient support, we have investigated the problems and possibly resolutions in this context. We have analyzed variability for these systems, using a systematic reuse prism, and identified a research gap in variability management. The analysis divides variability handling into four activities: (1) identify variability, (2) constrain variability, (3) implement variability, and (4) manage variability. Based on the findings we envision a reuse framework for the specific domain and present an example framework that addresses some of the identified challenges. We argue that it provides basic support for engineering self-adaptive software systems with systematic reuse. We discuss some important avenues of research for achieving the vision.

  • 28.
    Abbas, S.
    et al.
    Quaid-i-Azam University, Pakistan.
    Imtiaz-ud-Din,
    Quaid-i-Azam University, Pakistan.
    Mehmood, M.
    Quaid-i-Azam University, Pakistan.
    Raheel, A.
    Quaid-i-Azam University, Pakistan.
    Ayub, Rabia
    RISE Research Institutes of Sweden, Bioeconomy and Health, Biorefinery and Energy.
    Zahid, M.
    Higher Education Department Govt. of the Punjab, Pakistan.
    Tahir, M. N.
    University of Sargodha, Pakistan.
    Synthesis and Structural Characterization of Bioactive Ferrocenyl Substituted Hydrazones2021In: Russian journal of coordination chemistry, ISSN 1070-3284, E-ISSN 1608-3318, Vol. 47, no 12, p. 891-902Article in journal (Refereed)
    Abstract [en]

    A series of ferrocenyl substituted hydrazones (I–VII) derived from ferrocene carboxaldehyde and substituted hydrazides have been prepared and characterized by FTIR, 1H NMR spectroscopy, and crystallographic studies. The single-crystal X-ray analysis for III·0.5H2O·0.5CH3CN (CIF file CCDC no. 1968937) further authenticates the structural motif of the synthesized compounds. The C(11) of ferrocene carboxaldehyde is linked with N(1) of the hydrazide moiety with a bond length of 1.283(5) Å, confirming the binding of the two structural units present in the final product. They were preliminarily screened for their antimicrobial activity and demonstrate good results. The free radical scavenging activity for the compounds (III, IV) has been found to be more than 90% when compared with the ascorbic acid. The total antioxidant capacity and total reducing power assays for VI show significant activity whereas the data for the other compounds are also encouraging. Quantum chemical calculations at the DFT level predict that compound II is the softest while VII is the hardest within the series, resultantly II can be used as a synthon for further chemical reactions.

  • 29.
    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.

  • 30.
    Abbasi, A
    et al.
    NKT HV Cables AB, Sweden.
    Castellon, J
    University of Montpellier, France.
    Cavallini, A
    University of Bologna, Italy.
    Esterl, F
    TU Berlin, Germany.
    Götz, T
    TU Dresden, Germany.
    Kharezy, Mohammad
    RISE Research Institutes of Sweden, Safety and Transport, Measurement Technology.
    Markalous, S
    Megger, Germany.
    Neuhold, S
    FKH, Switzerland.
    Pietsch, R
    Highvolt, Germany.
    Pirker, A
    TU Graz, Austria.
    Plath, R
    TU Berlin, Germany.
    Riechert, U
    ABB Ltd, Switzerland.
    Rossner, M
    Hochschule Coburg, Germany.
    Seltzer- Grant, M
    HVPD Ltd, UK.
    Frietsche, R
    Siemens AG, Germany.
    Geissler, M
    Siemens AG, Germany.
    Kosse, M
    Siemens AG, Germany.
    Reuter, M
    Siemens AG, Germany.
    Hockbruckner, B
    Hochschule Würzburg-Schweinfurt, Germany.
    Kuchler, A
    Hochschule Würzburg-Schweinfurt, Germany.
    Progress on Partial Discharge Detectionunder DC Voltage Stress2019Conference paper (Other academic)
    Abstract [en]

    Detection and evaluation of partial discharges (PD) is important for quality assurance and diagnosis ofelectrical insulation systems. With increasing use of DC voltages in electrical transmission and distributionsystems, the field of PD under DC voltage stress needs to be further investigated.CIGRE Working Group D1.63 was approved for start in May 2015, where available knowledge and experiencein particular concerning the field distribution in insulation systems used in DC voltage systems, and thephysical processes of the PD phenomena under DC voltage stress should be reviewed. In order of guidingto meaningful procedures for DC PD measurements of HV equipment thorough understanding of i) thedifferences of PD behaviour between AC and DC with respect to the physical process and ii) influencingfactors of operating conditions (as e.g. polarization, temperature etc.) of different insulation systems underDC stress and respective effects on PD phenomena had to be examined.

  • 31.
    Abbasi, Shirin
    et al.
    Islamic Azad University, Iran.
    Rahmani, Amir
    National Yunlin University of Science and Technology, Douliou, Taiwan.
    Balador, Ali
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems. Mälardalen University, Sweden.
    Sahafi, Amir
    Islamic Azad University, Iran.
    Internet of Vehicles: Architecture, services, and applications2021In: International Journal of Communication Systems, ISSN 1074-5351, E-ISSN 1099-1131, Vol. 34, no 10, article id e4793Article in journal (Refereed)
    Abstract [en]

    The connection between objects and information exchange has been possible in recent years, with the advent of the Internet of Things (IoT) in different industries. We can meet different requirements in each industry utilizing this feature. Intelligent transportation uses the Internet of Vehicles (IoV) as a solution for communication among vehicles. It improves traffic management applications and services to guarantee safety on roads. We categorize services, applications, and architectures and propose a taxonomy for IoV. Then, we study open issues and challenges for future works. We highlighted applications and services due to drivers' requirements and nonfunctional requirements, considering the qualitative characteristic. This paper summarizes the current state of the IoV in architectures, services, and applications. It can be a start view to provide the solutions for challenges in traffic management in cities. The present study is beneficial for smart city developments and management. According to this paper's result, the services and applications evaluate performance with 34% frequency, safety and data accuracy, and security with a 13% frequency in selected papers. These measurements are essential due to the IoV characteristics such as real-time operation, accident avoidance in applications, and complicated user data management. 

  • 32.
    Abbaspour Assadollah, Sara
    et al.
    Mälardalen University, Sweden.
    Saadatmand, Mehrdad
    RISE, Swedish ICT, SICS.
    Eldh, Sigrid
    Ericsson AB, Sweden.
    Sundmark, Daniel
    Mälardalen University, Sweden.
    Hansson, Hans
    Mälardalen University, Sweden.
    A Model for Systematic Monitoring and Debugging of Starvation Bugs in Multicore Software2016In: Proceedings of the 1st International Workshop on Specification, Comprehension, Testing, and Debugging of Concurrent Programs (SCTDCP 2016), 2016, p. 7-11Conference paper (Refereed)
    Abstract [en]

    With the development of multicore hardware, concurrent, parallel and multicore software are becoming increasingly popular. Software companies are spending a huge amount of time and resources to nd and debug the bugs. Among all types of software bugs, concurrency bugs are also important and troublesome. This type of bugs is increasingly becoming an issue particularly due to the growing prevalence of multicore hardware. In this position paper, we propose a model for monitoring and debugging Starvation bugs as a type of concurrency bugs in multicore software. The model is composed into three phases: monitoring, detecting and debugging. The monitoring phase can support detecting phase by storing collected data from the system execution. The detecting phase can support debugging phase by comparing the stored data with starvation bug's properties, and the debugging phase can help in reproducing and removing the Starvation bug from multicore software. Our intention is that our model is the basis for developing tool(s) to enable solving Starvation bugs in software for multicore platforms.

  • 33.
    Abbaspour, Saadeh
    et al.
    Mälardalen University, Sweden; University of Qom, Iran.
    Fotouhi, Faranak
    University of Qom, Iran.
    Sedaghatbaf, Ali
    RISE Research Institutes of Sweden.
    Fotouhi, Hossein
    Mälardalen University, Sweden.
    Vahabi, Maryam
    Mälardalen University, Sweden; ABB Corporate Research, Sweden.
    Linden, Maria
    Mälardalen University, Sweden.
    A comparative analysis of hybrid deep learning models for human activity recognition2020In: Sensors, E-ISSN 1424-8220, Vol. 20, no 19, article id 5707Article in journal (Refereed)
    Abstract [en]

    Recent advances in artificial intelligence and machine learning (ML) led to effective methods and tools for analyzing the human behavior. Human Activity Recognition (HAR) is one of the fields that has seen an explosive research interest among the ML community due to its wide range of applications. HAR is one of the most helpful technology tools to support the elderly’s daily life and to help people suffering from cognitive disorders, Parkinson’s disease, dementia, etc. It is also very useful in areas such as transportation, robotics and sports. Deep learning (DL) is a branch of ML based on complex Artificial Neural Networks (ANNs) that has demonstrated a high level of accuracy and performance in HAR. Convolutional Neural Networks (CNNs) and Recurrent Neural Networks (RNNs) are two types of DL models widely used in the recent years to address the HAR problem. The purpose of this paper is to investigate the effectiveness of their integration in recognizing daily activities, e.g., walking. We analyze four hybrid models that integrate CNNs with four powerful RNNs, i.e., LSTMs, BiLSTMs, GRUs and BiGRUs. The outcomes of our experiments on the PAMAP2 dataset indicate that our proposed hybrid models achieve an outstanding level of performance with respect to several indicative measures, e.g., F-score, accuracy, sensitivity, and specificity. © 2020 by the authors.

  • 34.
    Abbaspour, Sara
    et al.
    RISE - Research Institutes of Sweden (2017-2019), ICT, Acreo. Mälardalen University, Sweden.
    Lindén, Maria
    Mälardalen University, Sweden.
    Gholamhosseini, Hamid
    Auckland University of Technology, New Zealand.
    Naber, Autumn
    Chalmers University of Technology, Sweden.
    Ortiz-Catalan, Max
    Integrum AB, Sweden.
    Evaluation of surface EMG-based recognition algorithms for decoding hand movements2019In: Medical and Biological Engineering and Computing, ISSN 0140-0118, E-ISSN 1741-0444, Vol. 58, no 1, p. 83-100Article in journal (Refereed)
    Abstract [en]

    Myoelectric pattern recognition (MPR) to decode limb movements is an important advancement regarding the control of powered prostheses. However, this technology is not yet in wide clinical use. Improvements in MPR could potentially increase the functionality of powered prostheses. To this purpose, offline accuracy and processing time were measured over 44 features using six classifiers with the aim of determining new configurations of features and classifiers to improve the accuracy and response time of prosthetics control. An efficient feature set (FS: waveform length, correlation coefficient, Hjorth Parameters) was found to improve the motion recognition accuracy. Using the proposed FS significantly increased the performance of linear discriminant analysis, K-nearest neighbor, maximum likelihood estimation (MLE), and support vector machine by 5.5%, 5.7%, 6.3%, and 6.2%, respectively, when compared with the Hudgins’ set. Using the FS with MLE provided the largest improvement in offline accuracy over the Hudgins feature set, with minimal effect on the processing time. Among the 44 features tested, logarithmic root mean square and normalized logarithmic energy yielded the highest recognition rates (above 95%). We anticipate that this work will contribute to the development of more accurate surface EMG-based motor decoding systems for the control prosthetic hands. [Figure not available: see fulltext.].

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  • 35.
    Abdelraheem, Mohamed Ahmed
    et al.
    RISE, Swedish ICT, SICS.
    Alizadeh, Javad
    Sharif University of Technology, Iran.
    Alkhzaimi, Hoda A.
    DTU Technical University of Denmark, Denmark.
    Aref, Mohammad Reza
    Sharif University of Technology, Iran.
    Bagheri, Nasour
    Shahid Rajaee Teachers Training University, Iran; IPM Institute for Research in Fundamental Sciences, Iran.
    Gauravaram, Praveen
    Queensland University of Technology, Australia.
    Improved Linear Cryptanalysis of reduced-round SIMON-32 and SIMON-482015In: Progress in Cryptology - INDOCRYPT 2015, 2015, Vol. 9462, p. 153-179Conference paper (Refereed)
    Abstract [en]

    In this paper we analyse two variants of SIMON family of light-weight block ciphers against linear cryptanalysis and present the best linear cryptanalytic results on these variants of reduced-round SIMON to date. We propose a time-memory trade-off method that finds differential/linear trails for any permutation allowing low Hamming weight differential/linear trails. Our method combines low Hamming weight trails found by the correlation matrix representing the target permutation with heavy Hamming weight trails found using a Mixed Integer Programming model representing the target differential/linear trail. Our method enables us to find a 17-round linear approximation for SIMON-48 which is the best current linear approximation for SIMON-48. Using only the correlation matrix method, we are able to find a 14-round linear approximation for SIMON-32 which is also the current best linear approximation for SIMON-32. The presented linear approximations allow us to mount a 23-round key recovery attack on SIMON-32 and a 24-round Key recovery attack on SIMON-48/96 which are the current best results on SIMON-32 and SIMON-48. In addition we have an attack on 24 rounds of SIMON-32 with marginal complexity.

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  • 36.
    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.

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  • 37.
    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.

  • 38.
    Abdul Hamid, Akram
    et al.
    Lund University, Sweden.
    von Platten, Jenny
    RISE Research Institutes of Sweden, Built Environment, System Transition and Service Innovation. Lund University, Sweden.
    Mjörnell, Kristina
    RISE Research Institutes of Sweden, Safety and Transport. Lund University, Sweden.
    Johansson, Dennis
    Lund University, Sweden.
    Bagge, Hans
    Lund University, Sweden.
    Impact of high residential density on the building technology, HVAC systems, and indoor environment in Swedish apartments2020In: E3S Web of Conferences. Volyme 172, 2020., EDP Sciences , 2020, article id 09003Conference paper (Refereed)
    Abstract [en]

    During the last few years, there has been an increased number of overcrowded apartments, due to increased migration but also housing shortage in general, particularly in the suburbs to major cities. The question is how the indoor environment in these apartments is affected by the high number of persons and how the problems related to high residential density can be overcome. This paper aims to specify the problem by investigating and analysing the technical parameters influenced by residential density in Swedish apartments built between 1965-1974. To map the situation, 11 interviews with employees at housing companies were conducted. Based on extreme conditions described in the interviews, simulations of the indoor climate and moisture risks at some vulnerable parts of constructions were made. Simulations were focused on moisture loads and CO2 concentrations as functions of residential density and ventilation rate. Finally, measures to combat problems associated to overcrowding are suggested. The aim is that the results should be used by authorities to formulate incentives and/or recommendations for housing companies to take actions to ensure a good indoor environment for all, irrespective of residential density conditions. © The Authors.

  • 39. Abele, S
    et al.
    Sjöberg, M
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Hamaide, T
    Zicmanis, A
    Guyot, A
    Reactive surfactants in heterophase polymerization. 10. Characterization of the surface activity of new polymerizable surfactants derived from maleic anhydride1997In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 13, p. 176-181Article in journal (Refereed)
    Abstract [en]

    Characterization of the surface activity of previously obtained polymerizable dialkyl maleates is performed to find out the relation between the structure of surfactants and their performances. The given polymerizable surfactants were synthesized for using in the emulsion polymerization. Three groups of dialkyl maleates-nonionic, cationic and zwitterionic-with different chain lengths of hydrophobic alkyl groups are investigated. Critical micelle concentration (cmc) values are determined for water soluble surfactants. It is found that cmc decreases with increasing chain length of the hydrophobic alkyl group. For nonionic and cationic surfactants interfacial tension at the interface between water and dodecane is measured. Droplet size in oil-in-water (O/W) emulsions is determined for all given surfactants. Cationic and zwitterionic dialkyl maleates with the longest investigated alkyl chain (R=C16H33, C17H35) provide good stability of O/W emulsions. In order to compare the obtained results, measurements with well-known surfactants-nonionic nonylphenol-poly(ethylene oxide) (NPEO10) and cationic hexadecyltrimethyl ammonium bromide (CTAB)-are performed.

  • 40.
    Abella, J.
    et al.
    Barcelona Supercomputing Center, Spain.
    Perez, J.
    BRTA Basque Research and Technology Alliance, Spain.
    Englund, Cristofer
    RISE Research Institutes of Sweden, Digital Systems, Mobility and Systems.
    Zonooz, B.
    Navinfo Europe, Netherlands.
    Giordana, G.
    AIKO Srl, Italy.
    Donzella, C.
    Exida Development Srl, Italy.
    Cazorla, F. J.
    Barcelona Supercomputing Center, Spain.
    Mezzetti, E.
    Barcelona Supercomputing Center, Spain.
    Serra, I.
    Barcelona Supercomputing Center, Spain.
    Brando, A.
    Barcelona Supercomputing Center, Spain.
    Agirre, I.
    BRTA Basque Research and Technology Alliance, Spain.
    Eizaguirre, F.
    BRTA Basque Research and Technology Alliance, Spain.
    Bui, Thanh
    RISE Research Institutes of Sweden, Digital Systems, Mobility and Systems.
    Arani, E.
    Navinfo Europe, Netherlands.
    Sarfraz, F.
    Navinfo Europe, Netherlands.
    Balasubramaniam, A.
    Navinfo Europe, Netherlands.
    Badar, A.
    Navinfo Europe, Netherlands.
    Bloise, I.
    AIKO Srl, Italy.
    Feruglio, L.
    AIKO Srl, Italy.
    Cinelli, I.
    AIKO Srl, Italy.
    Brighenti, D.
    Exida Engineering Srl, Italy.
    Cunial, D.
    Exida Engineering Srl, Italy.
    SAFEXPLAIN: Safe and Explainable Critical Embedded Systems Based on AI2023In: Proceedings -Design, Automation and Test in Europe, DATE, Institute of Electrical and Electronics Engineers Inc. , 2023Conference paper (Refereed)
    Abstract [en]

    Deep Learning (DL) techniques are at the heart of most future advanced software functions in Critical Autonomous AI-based Systems (CAIS), where they also represent a major competitive factor. Hence, the economic success of CAIS industries (e.g., automotive, space, railway) depends on their ability to design, implement, qualify, and certify DL-based software products under bounded effort/cost. However, there is a fundamental gap between Functional Safety (FUSA) requirements on CAIS and the nature of DL solutions. This gap stems from the development process of DL libraries and affects high-level safety concepts such as (1) explainability and traceability, (2) suitability for varying safety requirements, (3) FUSA-compliant implementations, and (4) real-time constraints. As a matter of fact, the data-dependent and stochastic nature of DL algorithms clashes with current FUSA practice, which instead builds on deterministic, verifiable, and pass/fail test-based software. The SAFEXPLAIN project tackles these challenges and targets by providing a flexible approach to allow the certification - hence adoption - of DL-based solutions in CAIS building on: (1) DL solutions that provide end-to-end traceability, with specific approaches to explain whether predictions can be trusted and strategies to reach (and prove) correct operation, in accordance to certification standards; (2) alternative and increasingly sophisticated design safety patterns for DL with varying criticality and fault tolerance requirements; (3) DL library implementations that adhere to safety requirements; and (4) computing platform configurations, to regain determinism, and probabilistic timing analyses, to handle the remaining non-determinism.

  • 41. Aberer, Karl
    et al.
    Onana Alima, Luc
    RISE, Swedish ICT, SICS.
    Ghodsi, Ali
    RISE, Swedish ICT, SICS.
    Girdzijauskas, Sarunas
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Hauswirth, Manfred
    Haridi, Seif
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    The essence of P2P: A reference architecture for overlay networks2005Conference paper (Refereed)
    Abstract [en]

    The success of the P2P idea has created a huge diversity of approaches, among which overlay networks, for example, Gnutella, Kazaa, Chord, Pastry, Tapestry, P-Grid, or DKS, have received specific attention from both developers and researchers. A wide variety of algorithms, data structures, and architectures have been proposed. The terminologies and abstractions used, however, have become quite inconsistent since the P2P paradigm has attracted people from many different communities, e.g., networking, databases, distributed systems, graph theory, complexity theory, biology, etc. In this paper we propose a reference model for overlay networks which is capable of modeling different approaches in this domain in a generic manner. It is intended to allow researchers and users to assess the properties of concrete systems, to establish a common vocabulary for scientific discussion, to facilitate the qualitative comparison of the systems, and to serve as the basis for defining a standardized API to make overlay networks interoperable.

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  • 42.
    Abi Nassif, L.
    et al.
    University Brest, France; University Saint Joseph, France.
    Rioual, S.
    University Brest, France.
    Farah, W.
    University Saint Joseph, France.
    Hellio, C.
    University Brest, France.
    Fauchon, M.
    University Brest, France.
    Trepos, R.
    University Brest, France.
    Abboud, M.
    University Saint Joseph, France.
    Diler, Erwan
    RISE Research Institutes of Sweden, Materials and Production, Corrosion.
    Thierry, Dominique
    RISE Research Institutes of Sweden, Materials and Production, Corrosion.
    Lescop, B.
    University Brest, France.
    Reduction of potential ennoblement of stainless steel in natural seawater by an ecofriendly biopolymer2020In: Journal of Environmental Chemical Engineering, E-ISSN 2213-3437, Vol. 8, no 1, article id 103609Article in journal (Refereed)
    Abstract [en]

    The effect of biofilm formation on passive stainless steel in seawater environments is of primary importance since it leads to potential ennoblement of surfaces and subsequently to localized corrosion such as pitting and crevice corrosion. This study aims at developing an ecofriendly alginate biopolymer containing both non-toxic calcium and a limited amount of biocidal zinc ions which inhibits this effect. For this purpose, calcium alginate containing less than 1 % of zinc ions localized in the vicinity of the steel surface in natural and renewed seawater is demonstrated to reduce significantly the ennoblement process of steel. After 1 month of immersion, a mass loss of only 4 % of the active material is observed authorizing thereby long-term protection of steel in real environment. 

  • 43.
    Abitbol, Tiffany
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Bioeconomy, Biorefinery and Energy.
    Ahniyaz, Anwar
    RISE - Research Institutes of Sweden (2017-2019), Bioscience and Materials, Surface, Process and Formulation.
    Swerin, Agne
    RISE - Research Institutes of Sweden (2017-2019), 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)
  • 44.
    Abitbol, Tiffany
    et al.
    RISE - Research Institutes of Sweden (2017-2019), 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.

  • 45. Abletshauser, C
    et al.
    Klüssendorf, D
    Schmidt, A
    Winkler, K
    März, W
    Buddecke, E
    Malmsten, M
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Biosensing of arteriosclerotic nanoplaque formation and interaction with an HMG-CoA reductase inhibitor2002In: Acta Physiologica Scandinavica, ISSN 0001-6772, E-ISSN 1365-201X, Vol. 176, p. 131-146Article in journal (Refereed)
    Abstract [en]

    Proteoheparan sulphate can be adsorbed to a methylated silica surface in a monomolecular layer via its transmembrane hydrophobic protein core domain. As a result of electrostatic repulsion, its anionic glycosaminoglycan side chains are stretched out into the blood substitute solution, thereby representing one receptor site for specific lipoprotein binding through basic amino acid-rich residues within their apolipoproteins. The binding process was studied by ellipsometric techniques suggesting that high-density lipoprotein (HDL) has a high binding affinity and a protective effect on interfacial heparan sulphate proteoglycan layers with respect to low-density lipoprotein (LDL) and Ca2+ complexation. Low-density lipoprotein was found to deposit strongly at the proteoheparan sulphate-coated surface, particularly in the presence of Ca2+, apparently through complex formation 'proteoglycan-LDL-calcium'. This ternary complex build-up may be interpreted as arteriosclerotic nanoplaque formation on the molecular level responsible for the arteriosclerotic primary lesion. On the other hand, HDL bound to heparan sulphate proteoglycan protected against LDL deposition and completely suppressed calcification of the proteoglycan-lipoprotein complex. In addition, HDL was able to decelerate the ternary complex deposition. Therefore, HDL attached to its proteoglycan receptor sites is thought to raise a multidomain barrier, selection and control motif for transmembrane and paracellular lipoprotein uptake into the arterial wall. Although much remains unclear regarding the mechanism of lipoprotein depositions at proteoglycan-coated surfaces, it seems clear that the use of such systems offers possibilities for investigating lipoprotein deposition at a 'nanoscopic' level under close to physiological conditions. In particular, Ca2+-promoted LDL deposition and the protective effect of HDL even at high Ca2+ and LDL concentrations agree well with previous clinical observations regarding risk and beneficial factors for early stages of atherosclerosis. Considering this, the system was tested on its reliability in a biosensor application in order to unveil possible acute pleiotropic effects of the lipid lowering drug fluvastatin. The very low-density lipoprotein (VLDL)/intermediate-density lipoprotein (IDL)/LDL plasma fraction from a high risk patient with dyslipoproteinaemia and type 2 diabetes mellitus showed beginning arteriosclerotic nanoplaque formation already at a normal blood Ca2+ concentration, with a strong increase at higher Ca2+ concentrations. Fluvastatin, whether applied to the patient (one single 80 mg slow release matrix tablet) or acutely in the experiment (2.2 μmol L-1), markedly slowed down this process of ternary aggregational nanoplaque complexation at all Ca2+ concentrations used. This action resulted without any significant change in lipid concentrations of the patient. Furthermore, after ternary complex build-up, fluvastatin, similar to HDL, was able to reduce nanoplaque adsorption and size. These immediate effects of fluvastatin have to be taken into consideration while interpreting the clinical outcome of long-term studies.

  • 46. Abo, H.
    et al.
    Eklund, David
    Kahle, T.
    Peterson, C.
    Eigenschemes and the Jordan canonical form2016In: Linear Algebra and Its Applications, Vol. 496, p. 121-151Article in journal (Refereed)
  • 47. Abraham, T
    et al.
    Kumpulainen, A
    Xu, Z
    Rutland, M
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Claesson, PM
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Masliyah, J
    Polyelectrolyte-mediated interaction between similarly charged surfaces: Role of divalent counter ions in tuning surface forces2001In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 17, p. 8321-8327Article in journal (Refereed)
    Abstract [en]

    The effects of divalent salts (CaCl2, MgCl2 and BaCl2) in promoting the adsorption of weakly charged polyelectrolyte (polyacrylic acid), PAA, Mw ~ 250000 g/mol) on mica surfaces and their role in tuning the nature of interactions between such adsorbed polyelectrolyte layers were studied using the interferometric surface forces apparatus. With mica surfaces in 3 mM MgCl2 solutions at pH ~8.0-9.0, the addition of 10 ppm PAA resulted in a long-range attractive bridging force and a short-range repulsive steric force. This force profile indicates a low surface coverage and weak adsorption. The range of the force can be related to the characteristic length scale RG of polyelectrolyte chains using a scaling description. An increase of the PAA concentration to 50 ppm changed the attractive force profile to a monotonic, long-range repulsive interaction extending up to 600 Å due to the increased surface coverage of polyelectrolyte chains on the mica surfaces. Comparison of the measured forces with a scaling mean field model suggests that the adsorbed polyelectrolyte chains are stretched, which eventually give rise to the polyelectrolyte brush like structure. When the mica surfaces were preincubated in 3 mM CaCl2 at pH ~8.0-9.0, in contrast to the case of 3 mM MgCl2, the addition of 10 ppm PAA resulted in a more complex force profile: long-range repulsive forces extending up to 800 Å followed by an attractive force regime and a second repulsive force regime at shorter separations. The long-range electrosteric forces can be attributed to strong adsorption of polyelectrolyte chains on mica surfaces (high surface coverage) which is facilitated by the presence of Ca2+ ions, while the intermediate range attractive forces can be ascribed to Ca2+ assisted bridging between adsorbed polyelectrolyte chains. Also interesting is to note various relaxation processes present in this system. In contrast to both MgCl2 and CaCl2 systems, with mica surfaces in 3 mM BaCl2 solution at pH ~8.0-9.0, the addition of 10 ppm PAA resulted in precipitation of polyelectrolyte chains on mica surfaces, resulting in an extremely long-range monotonic repulsive force profile. In summary, our study showed that divalent counterions (Mg2+, Ca2+, and Ba2+) exhibit significantly different behavior in promoting PAA adsorption on mica surfaces, modifying and controlling various surface interactions.

  • 48.
    Abrahamsson, Henrik
    RISE, Swedish ICT, SICS. School of Innovation, Design and Engineering.
    Network overload avoidance by traffic engineering and content caching2012Doctoral thesis, monograph (Other academic)
    Abstract [en]

    The Internet traffic volume continues to grow at a great rate, now driven by video and TV distribution. For network operators it is important to avoid congestion in the network, and to meet service level agreements with their customers. This thesis presents work on two methods operators can use to reduce links loads in their networks: traffic engineering and content caching. This thesis studies access patterns for TV and video and the potential for caching. The investigation is done both using simulation and by analysis of logs from a large TV-on-Demand system over four months. The results show that there is a small set of programs that account for a large fraction of the requests and that a comparatively small local cache can be used to significantly reduce the peak link loads during prime time. The investigation also demonstrates how the popularity of programs changes over time and shows that the access pattern in a TV-on-Demand system very much depends on the content type. For traffic engineering the objective is to avoid congestion in the network and to make better use of available resources by adapting the routing to the current traffic situation. The main challenge for traffic engineering in IP networks is to cope with the dynamics of Internet traffic demands. This thesis proposes L-balanced routings that route the traffic on the shortest paths possible but make sure that no link is utilised to more than a given level L. L-balanced routing gives efficient routing of traffic and controlled spare capacity to handle unpredictable changes in traffic. We present an L-balanced routing algorithm and a heuristic search method for finding L-balanced weight settings for the legacy routing protocols OSPF and IS-IS. We show that the search and the resulting weight settings work well in real network scenarios.

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  • 49.
    Abrahamsson, Henrik
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Traffic measurement and analysis1999Report (Other academic)
    Abstract [en]

    Measurement and analysis of real traffic is important to gain knowledge about the characteristics of the traffic. Without measurement, it is impossible to build realistic traffic models. It is recent that data traffic was found to have self-similar properties. In this thesis work traffic captured on the network at SICS and on the Supernet, is shown to have this fractal-like behaviour. The traffic is also examined with respect to which protocols and packet sizes are present and in what proportions. In the SICS trace most packets are small, TCP is shown to be the predominant transport protocol and NNTP the most common application. In contrast to this, large UDP packets sent between not well-known ports dominates the Supernet traffic. Finally, characteristics of the client side of the WWW traffic are examined more closely. In order to extract useful information from the packet trace, web browsers use of TCP and HTTP is investigated including new features in HTTP/1.1 such as persistent connections and pipelining. Empirical probability distributions are derived describing session lengths, time between user clicks and the amount of data transferred due to a single user click. These probability distributions make up a simple model of WWW-sessions.

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    FULLTEXT01
  • 50.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Ahlgren, Bengt
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Temporal Characteristics of Large IP Traffic Flows2003Report (Other academic)
    Abstract [en]

    Several studies of Internet traffic have shown that it is a small percentage of the flows that dominate the traffic. This is often referred to as the mice and elephants phenomenon. It has been proposed that this might be one of very few invariants of Internet traffic and that this property could somehow be used for traffic engineering purposes. The idea being that one in a scalable way could control a major part of the traffic by only keeping track of a small number of flows. But for this the large flows must also be stable in the meaning that they should be among the largest flows during long periods of time. In this work we analyse packet traces of Internet traffic and study the temporal characteristics of large aggregated traffic flows defined by destination address prefixes.

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    FULLTEXT01
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