Change search
Refine search result
415416417418419420421 20851 - 20900 of 26184
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 20851. Serrano, Erik
    et al.
    Blixt, Johan
    Enquist, Bertil
    Källsner, Bo
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP Trä.
    Oscarsson, Jan
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP Trä.
    Petersson, Hans
    Sterley, Magdalena
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP Trä.
    Wet glued laminated beams using side boards of Norway spruce2011Report (Refereed)
  • 20852.
    Serrano, Erik
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP Trä.
    Blumer, Samuel
    Gustafsson, P.J.
    Niemz, Peter
    Moisture induced stresses and deformations in parquet floors: An experimental and numerical study2007In: Wood Structure and Properties ’06, Arbora , 2007, , p. 481-484Conference paper (Refereed)
  • 20853.
    Serrano, Erik
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP Trä. Linnaeus University, Sweden; Lund University, Sweden.
    Enquist, B.
    Linnaeus University, Sweden.
    Vessby, J.
    Linnaeus University, Sweden.
    Long term in-situ measurements of displacement, temperature and relative humidity in a multi-storey residential CLT building2014Conference paper (Refereed)
    Abstract [en]

    In a multi-storey residential housing project comprising of four 8-storey timber buildings, the bottom storey being designed with concrete and storeys 2-8 in timber, the vertical relative displacement, the temperature and the relative humidity (RH) have been monitored. Displacement measurements started during construction and presented herein are results of 6.5 years of in-situ measurements. Temperature and relative humidity measurements have been ongoing for about 5.5 years. The temperature and RH measurements were performed at six different locations in the building, at each location in eight positions through the exterior wall with a sampling frequency of 1 measurement every 15 minutes. The results show that the total vertical displacement over six storeys after 6.5 years of service life is approximately 23 mm as a yearly average, and over the year the displacement varies from this value by approximately ±2 mm. The main cause for the relative displacement is the decrease of moisture content in the wood material leading to shrinkage after completion of the building. The results obtained show also that the exterior wall design of the building behaves well in terms of not comprising a general risk for damp or mould in the timber core of the external walls.

  • 20854.
    Serrano, Erik
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Enquist, Bertil
    Compression strength perpendicular to grain in cross-laminated timber (CLT)2010In: Proceedings of World Conference on Timber Engineering - WCTE 2010, World Conference on Timber Engineering , 2010, , p. 8Conference paper (Refereed)
  • 20855.
    Serrano, Erik
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Enquist, Bertil
    Contact-free measurement and non-linear finite element analyses of strain distribution along wood adhesive bonds2005In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 59, no 6, p. 641-646Article in journal (Refereed)
  • 20856.
    Serrano, Erik
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP Trä.
    Enquist, Bertil
    Vessby, Johan
    Vertical relative displacements in a medium-rise CLT-building2010In: ICSA 2010 - 1st International Conference on Structures & Architecture,, Taylor & Francis , 2010, , p. 388-395Conference paper (Refereed)
  • 20857.
    Serrano, Erik
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Fonselius, Mikael
    Johansson, Carl-Johan
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Solli, Kjell
    A method for glue bond quality testing of flange/web adhesive connections of wooden I-beams. Nordtest project 1583-022004Report (Refereed)
    Download full text (pdf)
    FULLTEXT01
  • 20858.
    Serrano, Erik
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut.
    Gustafsson, P.J.
    Fracture mechanics in timber engineering – Strength analyses of components and joints2007In: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873, Vol. 40, no 1, p. 87-96Article in journal (Refereed)
  • 20859. Serrano, Erik
    et al.
    Oscarsson, Jan
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Enquist, Bertil
    Sterley, Magdalena
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Petersson, Hans
    Källsner, Bo
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Green-glued laminated beams – High performance and added value2010In: Proceedings of World Conference on Timber Engineering - WCTE 2010, World Conference on Timber Engineering , 2010, , p. 1664-1669Conference paper (Refereed)
  • 20860.
    Serrano, Erik
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut. Linnaeus University, Sweden.
    Oscarsson, Jan
    RISE, SP – Sveriges Tekniska Forskningsinstitut.
    Sterley, Magdalena
    RISE, SP – Sveriges Tekniska Forskningsinstitut.
    Enquist, Bertil
    Linnaeus University, Sweden.
    Green-Glued Products for Structural Applications2014In: RILEM Bookseries, ISSN 2211-0844, E-ISSN 2211-0852, Vol. 9, p. 45-55Article in journal (Refereed)
    Abstract [en]

    The results from bending tests on 107 laminated, green-glued, beams manufactured from Norway spruce side boards are presented. The beams were made by face gluing 21-25 mm thick boards using a commercial one-component moisture curing polyurethane adhesive. In addition to the bending test results, results from shape stability measurements after climatic cycling and bond line strength and durability test results are also presented. The results from the bending tests show that, by applying very simple grading rules, it is possible to obtain beams with high bending strength (with a 5%-percentile characteristic value of 40,1 MPa) and substantial stiffness (mean value of 14360 MPa). Also the shape stability of the beams and the strength and the durability of the interlaminar bonds were found to be satisfactory.

  • 20861.
    Serrano, Erik
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP Trä.
    Sjödin, Johan
    Dowel type joints – Influence of moisture changes and dowel surface smoothness2007In: COST Action E55, COST Action E55 , 2007, , p. 17Conference paper (Other academic)
  • 20862. Serrano, Erik
    et al.
    Vessby, Johan
    Jarnerö, Kirsi
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Limnologen – 8 våningar klimatsmart byggande2010In: Samhällsbyggaren, ISSN 2000-2408, no 2, p. 28-31Article in journal (Other academic)
  • 20863.
    Serrano, Erik
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut.
    Vessby, Johan
    Olsson, Anders
    Modeling of Fracture in the Sill Plate in Partially Anchored Shear Walls2012In: Journal of Structural Engineering, ISSN 0733-9445, E-ISSN 1943-541X, Vol. 138, no 10, p. 1285–1288-Article in journal (Refereed)
  • 20864. Serrano, Erik
    et al.
    Vessby, Johan
    Olsson, Anders
    Girhammar, Ulf
    Källsner, Bo
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Design of Bottom Rails in Partially Anchored Shear Walls Using Fracture Mechanics2011Article in journal (Refereed)
  • 20865.
    Sesseng, Christian
    RISE - Research Institutes of Sweden (2017-2019), Safety and Transport, Fire Research Norway.
    Evergren, Franz
    RISE - Research Institutes of Sweden (2017-2019), Safety and Transport, Fire Research Norway.
    Brannsikkerhet ved bruk av gassbeholdere i bygg2018Report (Refereed)
    Abstract [no]

    Denne rapporten er utarbeidet på oppdrag fra Direktoratet for samfunnssikkerhet og beredskap (DSB). DSB har bedt RISE Fire Research om å bistå med evalueringer knyttet til bruken av gassbeholdere ved serveringssteder, overnattingssteder og forsamlingslokaler.

    Download full text (pdf)
    fulltext
  • 20866.
    Sesseng, Christian
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Fire Research AS, Norge.
    Kartlegging av bruk av røykvarslere i boliger i Norge2015In: Brandposten, no 53, p. 9-Article in journal (Other (popular science, discussion, etc.))
  • 20867.
    Sesseng, Christian
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Fire Research AS, Norge.
    Manglende brannforebyggning förte til storbrann2016In: Brandposten, no 55, p. 15-15Article in journal (Other academic)
  • 20868.
    Sesseng, Christian
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway.
    Fjær, Sindre
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway.
    Mapping of gas concentrations, effect of deadair space and effect of alternative detection technology in smouldering fires2016Report (Other academic)
    Abstract [en]

    Eight out of ten fire-related fatalities occur in dwellings. It is a fact that smoke detectors save lives, which emphasizes the importance of every home having a functioning smoke detector. In Norway, smoke detectors in dwellings are mandatory, and recommendations on which detector technology to use and the position of the detectors are given. Smoke detectors should be installed on the ceiling, outside of dead-air space (close to walls). In this study, ten smouldering fire experiments have been conducted to: • investigate if smoke detectors with CO sensing can alert residents at an earlier stage than photoelectric smoke detectors, consequently increasing chances of egress and survival for a sleeping person. • measure concentrations of toxic gases in a room where a smouldering fire occurs and investigate if tenability limits are exceeded when n photoelectric smoke detector is activated. • investigate if smoke detectors placed within dead-air space are activated at a later stage than smoke detectors placed according to the recommendations.

    Download full text (pdf)
    fulltext
  • 20869.
    Sesseng, Christian
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Fire Research AS, Norge.
    Optiske røykvarslere kan gi falsk trygghet på nattestid2015In: Brandposten, no 53, p. 8-Article in journal (Other (popular science, discussion, etc.))
  • 20870.
    Sesseng, Christian
    RISE - Research Institutes of Sweden (2017-2019), Safety and Transport, Fire Research Norway.
    Røykvarslere for bruk i bolig: Kartlegging av forskningsfront2012Report (Other academic)
    Abstract [no]

    I byggeforskrift av 1985 ble det innført krav til røykvarslere i nye boliger. I Forskrift om brannforebyggende tiltak og brannsyn (FOBTOB) av 1990, ble det i tillegg innført krav om røykvarslere i eksisterende boliger.

     Et litteraturstudium har blitt gjennomført for å kartlegge teknologistatus for røykvarslere i boliger. Det er lagt vekt på hvilken forskning og utvikling som er gjort med tanke på røykvarslere for boliger siden år 2000. Hvilke deteksjonsprinsipper kan benyttes, og kan ny teknologi gjøre detektorene bedre?

    Rapporten oppsummerer litteraturstudiet, innenfor forskjellige fokusområder, og gir i tillegg forslag til videre forskning på temaet.

    Download full text (pdf)
    fulltekst
  • 20871.
    Sesseng, Christian
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Fire Research AS, Norge.
    Reitan, Nina Kristine
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Fire Research AS, Norge.
    Experimental investigation of using CO sensors to detect smouldering fires in dwellings2016In: Suppression, Detection and Signaling Research and Applications Conference (SupDet 2016), 2016Conference paper (Other academic)
    Abstract [en]

    SP Fire Research has recently conducted a research project which demonstrated that CO sensors may be more suitable than photoelectric detectors for detecting smouldering fires at an early stage. This was done by experimentally comparing photoelectric detectors with CO sensor in simulated bedroom fires. The response times of the CO sensors were significantly faster than for the photoelectric detectors. Furthermore, whereas the levels of fire gases at the time of CO alarm activation were sub-toxic, the results indicate that the CO dose may exceed critical values before photoelectric detectors activated.

  • 20872.
    Sesseng, Christian
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway.
    Reitan, Nina Kristine
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway.
    Investigation of the use of smoke alarms in Norwegian dwellings2016In: Interflam 2016: Conference Proceedings, 2016, p. 387-388Conference paper (Refereed)
    Abstract [en]

    A survey mapping the use of smoke alarms and residents’ awareness of their legal obligations for protecting their dwellings with smoke alarms has been carried out. A total of 628 individual households geographically distributed throughout Norway were included in this study. The results demonstrated that factors such as level of education, age, gender, and if the dwelling is owned or rented by the resident, affects the awareness and compliance with the regulations and recommendations for the use of smoke alarms in dwellings.

  • 20873.
    Sesseng, Christian
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway.
    Reitan, Nina Kristine
    Fjær, Sindre
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway.
    Kartlegging av gasskonsentrasjoner, effekt av dødluftsrom og effekt av alternativt deteksjonsprinsipp ved ulmebrann2015Report (Other academic)
    Abstract [no]

    Åtte av ti som omkommer i brann dør i hjemmet. Det er stadfestet at røykvarslere redder liv, noe som understreker hvor viktig det er at alle hjem har fungerende røykvarsler. I Norge er det krav om at fungerende røykvarsler er installert i alle boliger, og det er også gitt anbefalinger om deteksjonsprinsipp og plassering av røykvarslere. Det er anbefalt å benytte optiske røykvarslere fremfor ioniske, og at disse monteres i tak, utenfor dødluftsrom (nær vegg). I denne studien er det utført ti forsøk med ulmebrann i et testrom innredet med en seng for å: • undersøke om røykdetektorer med CO-sensor kan varsle beboer på et tidligere tidspunkt enn optiske detektorer, og følgelig øke sjansene for evakuering. • kartlegge nivået av giftige gasser i et rom hvor ulmebrann oppstår, og undersøke om grenseverdiene for forgiftning er overskredet når en tradisjonell, optisk røykvarsler går til alarm. • undersøke om røykdetektorer som er plassert i dødluftsrom reagerer tregere enn detektorer som er plassert i henhold Norsk brannvernforenings anbefalinger.

    Download full text (pdf)
    fulltext
  • 20874.
    Sesseng, Christian
    et al.
    RISE Research Institutes of Sweden, Safety and Transport, Fire Technology.
    Reitan, Nina Kristine
    RISE Research Institutes of Sweden, Safety and Transport, Fire Technology.
    Storesund, Karolina
    RISE Research Institutes of Sweden, Safety and Transport, Fire Technology.
    Fjellgaard Mikalsen, Ragni
    RISE Research Institutes of Sweden, Safety and Transport, Fire Technology. Otto von Guericke University Magdeburg, Germany; Western Norway University of Applied Sciences, Norway.
    Hagen, Bjarne
    Western Norway University of Applied Sciences, Norway.
    Effect of particle granularity on smoldering fire in wood chips made from wood waste: An experimental study2020In: Fire and Materials, ISSN 0308-0501, E-ISSN 1099-1018, Vol. 44, no 4, p. 540-556Article in journal (Refereed)
    Abstract [en]

    Fires in wood waste storages cause financial losses, are difficult to extinguish, and emit large amounts of fire effluents. The mechanisms related to fires in wood chip piles are not well elucidated. To find suitable preventive measures for handling such fires in wood waste, a better understanding of the physical properties of wood waste is needed. The present study investigates how granularity affects mechanisms of smoldering fire and transition to flaming in wood chip piles. Eighteen experiments with samples inside a top-ventilated, vertical cylinder were conducted. Heating from underneath the cylinder induced auto-ignition and smoldering fire, and temperatures and mass loss of the sample were measured. The results showed that granularity significantly affects the smoldering fire dynamics. Material containing larger wood chips (length 4-100 mm) demonstrated more irregular temperature development, higher temperatures, faster combustion, and higher mass losses than material of smaller wood chips (length <4 mm). The larger wood chips also underwent transition to flaming fires. Flaming fires were not observed for small wood chips, which instead demonstrated prolonged and steady smoldering propagation. The differences are assumed to be partly due to the different bulk densities of the samples of large and small wood chips affecting the ventilation conditions. Increased knowledge about these combustion processes and transition to flaming is vital to develop risk-reducing measures when storing wood chips made from wood waste in piles.

  • 20875.
    Sesseng, Christian
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway.
    Storesund, Karolina
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway.
    Aamnes Mostue, Bodil
    SINTEF, Norway.
    Vurdering av brannvesenet: Kvaliteten i brannvesenets brannforebyggende arbeid2011Report (Other academic)
    Download full text (pdf)
    fulltext
  • 20876.
    Sesseng, Christian
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Safety and Transport, Fire Research Norway.
    Storesund, Karolina
    RISE - Research Institutes of Sweden (2017-2019), Safety and Transport, Fire Research Norway.
    Meraner, Christoph
    RISE - Research Institutes of Sweden (2017-2019), Safety and Transport, Fire Research Norway.
    Sæter Bøe, Andreas
    RISE - Research Institutes of Sweden (2017-2019), Safety and Transport, Fire Research Norway.
    Utvendig brannbekjempelse i Midtbykvartalet – En mulighetsstudie2019Report (Other academic)
    Abstract [en]

    External fire-fighting in Midtbykvartalet – A feasibility study

    The property developer E. C. Dahls Eiendom (ECDE) plans a building complex in a quarter in the city centre in Trondheim, the "Midtbykvartalet". The building will be enclosed by existing building blocks which to varying degrees hinder the fire service's access and efforts. Also, since the new building is intended for residential purposes, it will be necessary to install windows in fire rated walls against adjacent building. These factors result in deviations from a number of performance requirements in the guidelines to the regulations on technical requirements for construction works and there is therefore a need to find alternative solutions. It must be documented that these alternative solutions have at least as good an effect on fire safety as pre-accepted solutions would have. A potential side-effect of new, alternative solutions is that these can also, to some extent, protect the existing wooden buildings in the quarter.

    The aim of this report has been to identify the state-of-the-art within active fire protection measures for external fire-fighting and to obtain an overview of existing solutions and manufacturers and to carry out an assessment of the potential of these solutions.

    Risk scenarios

    An overview of existing buildings in the Midtbykvartalet is presented as well as an overall description of the plans for development. Based on this, several scenarios have been identified to reveal the potential fire-spread hazard between the existing buildings and the planned building. Furthermore, a qualitative risk assessment has been carried out.

    A literature study describes the state-of-the-art in water-based extinguishing systems for outdoor use. It deals with fixed extinguishers (facade sprinklers, water curtains), dynamic extinguishers, foam extinguishers, fire gels, as well as with sprinkler systems' effect and reliability. Furthermore, existing solutions (e.g. facade sprinklers, water curtains, water cannons and water mist turbines) have been surveyed, existing documentation described and assessed regarding suitability for use in the Midtbykvartalet.

    From the identified scenarios, it appears that fires in existing buildings are more likely to spread to the new building than a fire from the new building to existing buildings. The greatest danger to the new building will be if a fire spreads in existing buildings, up through the roof, through windows or along the facade to the roof. In many cases, the fire service will have good access with their ladder trucks etc. to perform extinguishing efforts, at least in the early phase of the fire. But the risk of rapid internal fire spread, which may include several of the older buildings, can create a challenging situation for the fire service and a risk for the new building. In case of fire spread to the new building, the fire department will, due to the position and height of the building, have difficulty with aerial rescue and evacuation from the new building's higher floors.

    Concept for the Midtbykvartalet

    A combination of a static and a dynamic extinguishing system will provide the best balance between system robustness, extinguishing effect and flexibility for the Midtbykvartalet. Facade sprinklers are considered the most suitable static system solution. Facade sprinklers will primarily cool the facade of the new building and absorb heat radiation from a potential fire in the existing buildings, but will not be suitable for extinguishing or actively fighting a fire within the existing buildings. The design and planning of facade sprinklers shall take the design of windows, balconies and roof terraces into account, which have been identified as vulnerable points in the firewalls.

    Dynamic systems such as water cannons and water mist turbines can be used to cool facades and to actively fight a fire over relatively long distances. In addition, such systems can be established so that the fire service can take over control of the extinguishing system as needed. This property is important, because of the height of the new building and because of how it is surrounded by existing buildings.

    Both water cannons and water mist turbines can be combined with an automatic control that allows you to fight a fire at an early stage, even before the arrival of the fire service, as long as early detection is achieved. A fire that spreads within the existing buildings will not be possible to extinguish with permanently installed dynamic systems. Therefore, the cooling and extinguishing effect of such systems must be evaluated based on the scenario of a large fire in the neighbouring building, which has not been done before.

    The cooling and extinguishing effects for both systems are largely dependent on their control system. The control system must be capable of aiming the water cannon or the water mist turbine at the fire, if required compensating for wind effects and selecting an appropriate water jet mode. Therefore, in order to adapt the control system to the Midtbykvartalet, it is necessary to quantify the cooling and extinguishing effect of such a system in advance and with regard to a potentially large fire in the adjacent existing buildings.

    Selected water mist turbines have the option of operating in a full jet mode, like a water cannon. Therefore, such systems are considered more flexible than water cannons. However, water mist turbines set large amounts of air in motion and generate turbulence that can affect the fire. It is therefore important to investigate if and in which cases this can aggravate the fire and have a negative effect on other areas in the quarter.

    Download full text (pdf)
    fulltext
  • 20877.
    Sesseng, Christian
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway.
    Storesund, Karolina
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway.
    Steen-Hansen, Anne
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway.
    Analyse av dødsbranner i Norge i perioden 2005 - 20142017Report (Other academic)
    Abstract [no]

    I denne studien er informasjon fra brannstatistikk og andre kilder fra perioden 2005 – 2014 analysert, for å få mer detaljert kunnskap om hvem som omkommer i brann og hvorfor de omkommer. Dermed kan tiltak iverksettes mer målrettet for å redusere antall omkomne.  Følgende spørsmål er forsøkt besvart i studien: 1. Hvilke risikofaktorer forbindes med de som omkommer i branner i Norge? 2. Hva er årsakene til dødsbranner i Norge? 3. Hvordan kan dødsbranner best forebygges?  I den aktuelle perioden er det registrert 517 branner med 571 omkomne. Vi har kartlagt informasjon fra 347 politirapporter, identifisert 387 omkomne og trukket ut informasjon fra pasientjournalene til 248 av de omkomne.

    Download full text (pdf)
    fulltext
  • 20878.
    Sesseng, Christian
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway.
    Storesund, Karolina
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway.
    Steen-Hansen, Anne
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway.
    Analysis of 985 fire incidents related to oil- and gas production on the Norwegian shelf2018In: Safety and Reliability: Safe Societies in a Changing World / [ed] Stein Haugen, Anne Barros, Coen van Gulijk, Trond Kongsvik, Jan Erik Vinnem, 2018, Vol. 1, p. 1847-1854Conference paper (Refereed)
    Abstract [en]

    Fire is a major threat in the petroleum industry. However, little has been published about the fire related incidents that have occurred in the Norwegian petroleum sector. To gain more knowledge, data from 985 incidents in the 1997 - 2014 period has been analysed. Examples of factors studied are type of facility involved, involved area or system, consequences and severity level. The analysis of the fire incidents reveals that even though many incidents are reported, the large majority of these have not imposed risks for severe fire accidents. It has also provided valuable information regarding possible dangerous situations, commonly in-volved areas, types of equipment as well as types of activity that were involved. Twenty-nine percent of the incidents were false alarms, which must be regarded as a high number in an industry where any production stop could be extremely costly.

    Download full text (pdf)
    fulltext
  • 20879.
    Sesseng, Christian
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway.
    Storesund, Karolina
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway.
    Steen-Hansen, Anne
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway.
    Analysis of 985 fire incidents related to oil-and gas production on the Norwegian continental shelf2018In: Safety and Reliability - Safe Societies in a Changing World - Proceedings of the 28th International European Safety and Reliability Conference, ESREL 2018, 2018, p. 1847-1854Conference paper (Refereed)
    Abstract [en]

    Fire is a major threat in the petroleum industry. However, little has been published about the fire related incidents that have occurred in the Norwegian petroleum sector. To gain more knowledge, data from 985 incidents in the 1997–2014 period has been analysed. Examples of factors studied are type of facility involved, involved area or system, consequences and severity level. The analysis of the fire incidents reveals that even though many incidents are reported, the large majority of these have not imposed risks for severe fire accidents. It has also provided valuable information regarding possible dangerous situations, commonly involved areas, types of equipment as well as types of activity that were involved. Twenty-nine percent of the incidents were false alarms, which must be regarded as a high number in an industry where any production stop could be extremely costly.

  • 20880.
    Sesseng, Christian
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway.
    Storesund, Karolina
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway.
    Steen-Hansen, Anne
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway.
    Analysis of fatal fires in Norway in the 2005 – 2014 period2017Report (Other academic)
    Abstract [en]

    In this study, information from fire statistics and other sources has been analyzed to get more detailed knowledge than before about who dies in fires and why. This will help to implement more targeted measures in order to reduce the number of people perishing in fires.  The study attempted to answer the following questions: 1. What risk factors are associated with those who perish in fires in Norway? 2. What are the causes of fatal fires in Norway? 3. How can fatal fires best be prevented?  A total of 517 fires with 571 fatalities are registered in the official fire statistics in the 2005 – 2014 period. We have examined 347 police investigation reports, identified 387 deceased and  extracted information from 248 medical records.

    Download full text (pdf)
    fulltext
  • 20881.
    Sesseng, Christian
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway.
    Storesund, Karolina
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway.
    Steen-Hansen, Anne
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway.
    Analysis of fatal fires in Norway over a decade, – A retrospective observational study2018In: Safety and Reliability - Safe Societies in a Changing World - Proceedings of the 28th International European Safety and Reliability Conference, ESREL 2018, 2018, p. 2837-2844Conference paper (Refereed)
    Abstract [en]

    Five-hundred-and-seventy-one fatalities were registered in the official fire statistics in Norway between 2005–2014. However, little is known about the victims. This study collected information from several sources to build a holistic database and gain more knowledge about the technical and social aspects of the incidents, forming a basis for more targeted measures. Human behaviour greatly affects the risk of fire, which supports why social aspects of incidents should be considered when identifying risk factors associated with the victims. The results showed a clear distinction between victims above and below the age of 67 with respect to risk factors. For the elderly, reduced mobility, impaired cognitive ability, mental disorders and smoking were observed risk factors. For the younger victims known substance abuse, mental illness, alcoholic influence and smoking were observed, mostly in combination. This shows that fire is a social problem, and should be prevented by initiating customised measures

  • 20882.
    Sesseng, Christian
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway.
    Storesund, Karolina
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway.
    Steen-Hansen, Anne
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway.
    Evaluation of an industrial building inferno – A case study2019In: Interflam 2019: Conference Proceedings, 2019Conference paper (Refereed)
  • 20883.
    Sesseng, Christian
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway.
    Storesund, Karolina
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway.
    Steen-Hansen, Anne
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway.
    Wighus, Ragnar
    RISE - Research Institutes of Sweden, ICT, Viktoria.
    Evaluering av brannen i BASA-Huset, Tønsberg2016Report (Refereed)
    Abstract [no]

    Torsdag 23. juli 2015 brøt det ut brann i BASA-Huset i Tønsberg. BASA-Huset var et næringsbygg hvor ca. 70 firma hadde tilhold. Størsteparten av bygget brant ned, og forsikringserstatningene er anslått til å være i størrelsesorden flere hundre millioner kroner. Direktoratet for samfunnssikkerhet og beredskap og Direktoratet for byggkvalitet har bedt SP Fire Research om å evaluere brannen med tanke på hvorfor brannen ble så stor som den ble, og hvilke nasjonale læringspunkt som kan dras ut av hendelsen.

  • 20884.
    Seth Caous, Josefin
    et al.
    Chalmers University of Technology, Sweden; Nobel Biocare AB, Sweden.
    Lövenklev, Maria
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SIK – Institutet för livsmedel och bioteknik.
    Fäldt, Jenny
    Nobel Biocare AB, Sweden.
    Langton, Maud
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SIK – Institutet för livsmedel och bioteknik. SLU Swedish University of Agricultural Sciences, Sweden.
    Adhesion of Streptococcus mitis and Actinomyces oris in co-culture to machined and anodized titanium surfaces as affected by atmosphere and pH2013In: BMC Oral Health, ISSN 1472-6831, E-ISSN 1472-6831, Vol. 13, no 1, article id 4Article in journal (Refereed)
    Abstract [en]

    Background: With the rising demand for osseointegrated titanium implants for replacing missing teeth, often in patients with a history of periodontitis, implant-related infections have become an issue of growing concern. Novel methods for treating and preventing implant-associated infections are urgently needed. The aim of this study was to investigate if different pH, atmosphere and surface properties could restrict bacterial adhesion to titanium surfaces used in dental implants. Methods: Titanium discs with machined or anodized (TiUnite™) surface were incubated with a co-culture of Streptococcus mitis and Actinomyces oris (early colonizers of oral surfaces) at pH 5.0, 7.0 and 9.0 at aerobic or anaerobic atmosphere. The adhesion was analysed by counting colony forming (CFU) units on agar and by confocal laser scanning microscopy (CLSM).Results: The CFU analysis showed that a pH of 5.0 was found to significantly decrease the adhesion of S. mitis, and an aerobic atmosphere, the adhesion of A. oris. S. mitis was found in significantly less amounts on the anodized surface than the machined surface, while A. oris was found in equal amounts on both surfaces. The CLSM analysis confirmed the results from the CFU count and provided additional information on how the two oral commensal species adhered to the surfaces: mainly in dispersed clusters oriented with the groves of the machined surface and the pores of the anodized surface. Conclusions: Bacterial adhesion by S. mitis and A. oris can be restricted by acidic pH and aerobic atmosphere. The anodized surface reduced the adhesion of S. mitis compared to the machined surface; while A. oris adhered equally well to the pores of the anodized surface and to the grooves of the machined surface. It is difficult to transfer these results directly into a clinical situation. However, it is worth further investigating these findings from an in vitro perspective, as well as clinically, to gain more knowledge of the effects acid pH and aerobic atmosphere have on initial bacterial adhesion.

  • 20885.
    Seth Caous, Josefin
    et al.
    RISE Research Institutes of Sweden, Materials and Production, Product Realisation Methodology. University of Gothenburg, Sweden.
    Svensson Malchau, K.
    University of Gothenburg, Sweden; Sahlgrenska University Hospital, Sweden.
    Petzold, M.
    University of Gothenburg, Sweden.
    Fridell, Y.
    Sahlgrenska University Hospital, Sweden.
    Malchau, H.
    University of Gothenburg, Sweden; Sahlgrenska University Hospital, Sweden: Harvard University, USA.
    Ahlstrom, L.
    University of Gothenburg, Sweden; Sahlgrenska University Hospital, Sweden.
    Grant, P.
    University of Gothenburg, Sweden; Lovisenberg Diakonale Hospital, Norway.
    Erichsen Andersson, A.
    University of Gothenburg, Sweden; Sahlgrenska University Hospital, Sweden.
    Instrument tables equipped with local unidirectional airflow units reduce bacterial contamination during orthopedic implant surgery in an operating room with a displacement ventilation system2022In: Infection Prevention in Practice, E-ISSN 2590-0889, Vol. 4, no 3, article id 100222Article in journal (Refereed)
    Abstract [en]

    Background: Airborne bacteria present in the operating room may be a cause of surgical site infection, either contaminating the surgical wound directly, or indirectly via e.g. surgical instruments. The aim of this study was to evaluate if instrument and assistant tables equipped with local unidirectional airflow reduce bacterial contamination of the instrument area to ultra clean levels, during orthopedic implant surgery in an operating room with displacement ventilation. Methods: Local airflow units of instrument and assistant tables were either active or inactive. Colony forming units were sampled intraoperatively from the air above the instruments and from instrument dummies. A minimum of three air samples and two-three samples from instrument dummies were taken during each surgery. Samples were incubated on agar for total aerobic bacterial count. The mean air and instrument contamination during each surgery was calculated and used to analyze the difference in contamination depending on use of local airflow or not. All procedures were performed in the same OR. Results: 188 air and 124 instrument samples were collected during 48 orthopedic implant procedures. Analysis showed that local unidirectional airflow above the surgical instruments significantly reduced the bacterial count in the air above assistant table (P<0.001) and instrument table (P=0.002), as well as on the instrument dummies from the assistant table (P=0.001). Conclusions: Instrumentation tables equipped with local unidirectional airflow protect the surgical instruments from bacterial contamination during orthopedic implant surgery and may therefore reduce the risk of indirect wound contamination. © 2022 The Authors

  • 20886.
    Sethi, Jatin
    et al.
    KTH Royal Institute of Technology, Sweden.
    Glowacki, Eric
    Linköping University, Sweden; Brno University of Technology, Czech Republic.
    Reid, Michael
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design. KTH Royal Institute of Technology, Sweden.
    Larsson, Per A.
    KTH Royal Institute of Technology, Sweden.
    Wågberg, Lars
    KTH Royal Institute of Technology, Sweden.
    Ultra-thin parylene-aluminium hybrid coatings on nanocellulose films to resist water sensitivity2024In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 323, article id 121365Article in journal (Refereed)
    Abstract [en]

    Non-sustainable single-use plastics used for food packaging needs to be phased out. Films made from cellulose nanofibrils (CNFs) are suitable candidates for biodegradable and recyclable packaging materials as they exhibit good mechanical properties, excellent oxygen barrier properties and high transparency. Yet, their poor water vapour barrier properties have been a major hindrance in their commercialisation. Here, we describe the preparation of 25 μm thick CNF films with significantly improved water vapour barrier properties after deposition of ultrathin polymeric and metallic coatings, parylene C and aluminium, respectively. When first adding a 40 nm aluminium layer followed by an 80 nm parylene layer, i.e. with a combined thickness of less than one percent of the CNF film, a water vapour transmission rate of 2.8 g m−2 d−1 was achieved at 38 °C and 90 % RH, surpassing a 25 μm polypropylene film (4–12 g m−2 d−1). This is an improvement of more than 700 times compared to uncoated CNF films, under some of the harshest possible conditions a packaging material will need to endure in commercial use. The layers showed a good and even coverage, as assessed by atomic force microscopy, and the parylene-coated surfaces were hydrophobic with a contact angle of 110°, providing good water repellency. 

  • 20887.
    Sette, Erik
    et al.
    Chalmers University of Technology, Sweden.
    Pallars, David
    Chalmers University of Technology, Sweden.
    Johnsson, Filip
    Chalmers University of Technology, Sweden.
    Ahrentorp, Fredrik
    RISE, Swedish ICT, Acreo.
    Ericsson, Anders
    RISE, Swedish ICT, Acreo.
    Johansson, Christer
    RISE, Swedish ICT, Acreo.
    Magnetic tracer-particle tracking in a fluid dynamically down-scaled bubbling fluidized bed2015In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 138, p. 368-377Article in journal (Refereed)
    Abstract [en]

    A method for 3-dimensional (3D) magnetic tracer particle tracking in a fluid dynamically downscaled fluidized bed is presented. The method applies anisotropic magnetoresistive (AMR) sensors to track a magnetic tracer particle in the form of an NdFeB-based permanent magnet. The fluid dynamically downscaled bed has a cross-section of 0.17 × 0.17 m2and is operated at ambient conditions with bronze powder as bulk solids and the tracer particle corresponding to a fuel particle. After up-scaling the bed corresponds to a 0.85 × 0.85 m2 bed of fuel ash or silica sand operated with air at 900 °C using anthracite coal as a fuel. Thus, the method provides continuous tracking of the tracer particle trajectorywhich, combined with the fluid dynamic scaling yields quantitativeinformation applicable to the study of fuel mixing in large-scale fluidized-bed processes operating under hot conditions. Application of the method represents a significant step forward compared to other experimental studies which are limited to qualitative interpretations; performed in 2D units and in cold 3D units which are not fluid dynamically scaled.

    It is shown that the AMR sensor system is able to work with the (non-magnetic) bronze powder resulting from the fluid dynamical downscaling, i.e. overcoming the limitation in signal penetration which prevents tracking of radioactive objects in such dense media. Thus, successful application of the AMR method for continuous 3D object tracking in a fluid dynamically downscaled unit is demonstrated for the first time. The measurement system provides both translational and rotational data, unleashing possibilities also as a validation tool of CFD models. The preliminary results show a spatial resolution on the order of 1 mm, while temporal resolution is on the order of milliseconds.

  • 20888.
    Sewring, Tor
    et al.
    Chalmers University of Technology, Sweden; KTH Royal Institute of Technology, Sweden.
    Zhu, Weizhen
    Chalmers University of Technology, Sweden; Stora Enso; Sweden.
    Sedin, Maria
    RISE, Innventia.
    Theliander, Hans
    Chalmers University of Technology, Sweden; KTH Royal Institute of Technology, Sweden.
    Estimation of the deprotonation degree of phenolic groups on kraft lignin2015In: NWBC 2015: The 6th Nordic Wood Biorefinery Conference, Espoo: VTT , 2015, p. 442-449Conference paper (Refereed)
    Abstract [en]

    Research has been undertaken into the deprotonation degree of the phenolic groups on softwood kraft lignin in black liquor. An attempt was made to mathematically model the ion concentration distributions around lignin fragments in black liquor by studying the possibility of using a modified Poisson-Boltzmann cell model and extending the validity of this model by extrapolating the valid ionic concentration range using the Pitzer method. The model has been utilised to predict the pH dependent deprotonation degree under various conditions that are relevant to the LignoBoost process. It has been demonstrated that the pH and temperature strongly affected the deprotonation degree of phenolic groups on kraft lignin. The effect of the molecular weight of lignin and a small increase in ionic strength on the deprotonation degree was very small in black liquor systems of high ionic strength. It was observed that the pH at the surface of lignin macromolecules was approximately the same in black liquor systems of high ionic strength.

  • 20889.
    Sewring, Tor
    et al.
    Chalmers University of Technology, Sweden.
    Zhu, Weizhen
    Chalmers University of Technology, Sweden.
    Sedin, Maria
    RISE - Research Institutes of Sweden, Bioeconomy, Papermaking and Packaging.
    Theliander, Hans
    KTH Royal Institute of Technology, Sweden; Chalmers University of Technology, Sweden.
    Predictions of Pair Interaction Potentials between Kraft Lignin Macromolecules in Black Liquors by Utilization of a Modified Poisson-Boltzmann Approach2019In: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 58, no 8, p. 3427-3439Article in journal (Refereed)
    Abstract [en]

    In this investigation, a modified Poisson-Boltzmann approach has been used to estimate the mean ion concentration distributions of ionic species present in black liquors around charged kraft lignin macromolecules at industrially relevant conditions. The distributions were utilized to predict the double layer repulsion and, further, predict the overall pair interaction potentials between two kraft lignin macromolecules or particles immersed in the black liquor electrolyte. The properties of softwood black liquors were used as input data to the model. The numerical results predicted the pair interaction potentials to remain repulsive up to salt concentrations of about 2.5 M at pOH 1. The critical coagulation concentration of salt was predicted to decrease as the pOH of the black liquor was increased. The predictions at 65 °C and moderate levels of pOH (3.5) and salt concentration (1.9 M) were found to be in good agreement with previous observations reported in the literature.

  • 20890.
    Seyed Hoseini Nazari, Mohammed
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Bygg och Mekanik. Chalmers University of Technology.
    Wear characteristics of materials for artificial hip joints2005Doctoral thesis, monograph (Other academic)
  • 20891. Sha’ameri, Ahmad Zuri
    et al.
    Kanaa, Abdulrahman
    Robust multiple channel scanning and detection of low probability of intercept (LPI) communication signals2016In: Defense S&T technical bulletin, Vol. 9, no 1, p. 1-17Article in journal (Refereed)
  • 20892.
    Shafa, Muhammad
    et al.
    Xi’an Jiaotong University, China; Yulin University, China.
    Wu, Di
    Xi’an Jiaotong University, China.
    Chen, Xi
    Xi’an Jiaotong University, China.
    Ul Hassan Alvi, Naveed
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Pan, Yi
    Xi’an Jiaotong University, China.
    Najar, Adel
    United Arab Emirates University United Arab Emirates.
    Flexible infrared photodetector based on indium antimonide nanowire arrays2021In: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 32, no 27, article id 27LT01Article in journal (Refereed)
    Abstract [en]

    Narrow bandgap semiconductors like indium antimonide (InSb) are very suitable for high-performance room temperature infrared photodetectors, but the fragile nature of the wafer materials hinders their application as flexible/wearable devices. Here, we present a method to fabricate a photodetector device of assembled crystalline InSb nanowire (NW) arrays on a flexible substrate that balances high performance and flexibility, facilitating its application in wearable devices. The InSb NWs were synthesized by means of a vapor-liquid-solid technique, with gold nanoclusters as seeding particles. The morphological and crystal properties were investigated using scanning electron microscopy, x-ray diffraction and high-resolution transmission electron microscopy, which revealed the unique spike shape and high crystallinity with (111) and (220) planes of InSb NWs. The flexible infrared photodetector devices were fabricated by transferring the NWs onto transparent and stretchable polydimethylsiloxane substrate with pre-deposited gold electrodes. Current versus time measurement of the photodetector devices under light showed photoresponsivity and sensitivity to mid-infrared at bias as low as 0.1 V while attached to curved surfaces (suitable for skin implants). A high-performance NW device yielded efficient rise and decay times down to 1 s and short time lag for infrared detection. Based on dark current, calculated specific detectivity of the flexible photodetector was 1.4 × 1012Jones. The performance and durability render such devices promising for use as wearable infrared photodetectors.

  • 20893.
    Shafaat, Tallat M.
    RISE, Swedish ICT, SICS. School of Information and Communication Technology.
    Dealing with Network Partitions and Mergers in Structured Overlay Networks2009Licentiate thesis, monograph (Other academic)
  • 20894.
    Shafaat, Tallat M.
    RISE, Swedish ICT, SICS, Computer Systems Laboratory. School of Information and Communication Technology.
    Partition Tolerance and Data Consistency in Structured Overlay Networks2013Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Structured overlay networks forma major class of peer-to-peer systems, which are used to build scalable, fault-tolerant and self-managing distributed applications. This thesis presents algorithms for structured overlay networks, on the routing and data level, in the presence of network and node dynamism. On the routing level, we provide algorithms for maintaining the structure of the overlay, and handling extreme churn scenarios such as bootstrapping, and network partitions and mergers. Since any long lived Internet-scale distributed system is destined to face network partitions, we believe structured overlays should intrinsically be able to handle partitions and mergers. In this thesis, we discuss mechanisms for detecting a network partition and merger, and provide algorithms for merging multiple ring-based overlays. Next, we present a decentralized algorithm for estimating the number of nodes in a peer-to-peer system. Lastly, we discuss the causes of routing anomalies (lookup inconsistencies), their effect on data consistency, and mechanisms on the routing level to reduce data inconsistency. On the data level, we provide algorithms for achieving strong consistency and partition tolerance in structured overlays. Based on our solutions on the routing and data level, we build a distributed key-value store for dynamic partially synchronous networks, which is linearizable, self-managing, elastic, and exhibits unlimited linear scalability. Finally,we present a replication scheme for structured overlays that is less sensitive to churn than existing schemes, and allows different replication degrees for different key ranges that enables using higher number of replicas for hotspots and critical data.

    Download full text (pdf)
    FULLTEXT01
  • 20895.
    Shafaat, Tallat M.
    et al.
    RISE, Swedish ICT, SICS. Computer Systems Laboratory.
    Ahmad, Bilal
    KTH Royal Institute of Technology, Sweden.
    Haridi, Seif
    RISE, Swedish ICT, SICS. Computer Systems Laboratory.
    ID-Replication for Structured Peer-to-Peer Systems2012Conference paper (Refereed)
    Abstract [en]

    Structured overlay networks, like any distributed system, use replication to avoid losing data in the presence of failures. In this paper, we discuss the short-comings of existing replication schemes and propose a technique for replication, called ID-Replication. ID-Replication allows different replication degrees for keys in the system, thus allowing popular data to have more copies. We discuss how ID-Replication is less sensitive to churn compared to existing replication schemes, which makes ID-Replication better suited for building consistent services on top of overlays compared to other schemes. Furthermore, we show why ID-Replication is simpler to load-balance and more secure compared to successor-list replication. We evaluate our scheme in detail, and compare it with successor-list replication.

  • 20896.
    Shafaat, Tallat M.
    et al.
    RISE, Swedish ICT, SICS. KTH Royal Institute of Technology, Sweden.
    Ghodsi, Ali
    RISE, Swedish ICT, SICS. University of California, USA.
    Haridi, Seif
    RISE, Swedish ICT, SICS.
    Dealing with Bootstrapping, Maintenance, and Network Partitions and Mergers in Structured Overlay Networks2012Conference paper (Refereed)
    Abstract [en]

    In the last decade, numerous structured overlay networks were proposed as a scalable infrastructure to build large-scale distributed systems under dynamic environments. These overlays were touted to be fault-tolerant and self-managing, yet, as we show in this paper, they fall short of handling some extreme scenarios they envision. These scenarios include bootstrapping, and underlying network partitions and mergers. We argue that handling such extreme scenarios is fundamental to providing a fault-tolerant and self-managing system, and thus, structured overlay networks should intrinsically be able to handle them. In this paper, we present ReCircle, an overlay algorithm that apart from performing periodic maintenance to handle churn like any other overlay, can merge multiple structured overlay networks. We show how such an algorithm can be used for decentralized bootstrapping. ReCircle does not have any extra cost during normal maintenance compared to an isolated overlay maintenance algorithm. Furthermore, the algorithm is tunable to tradeoff between bandwidth consumption and time to convergence during extreme events like bootstrapping and handling network partitions and mergers. We evaluate the algorithm extensively under various scenarios through simulation and experimentation on Planet Lab.

  • 20897.
    Shafaat, Tallat M.
    et al.
    RISE, Swedish ICT, SICS, Computer Systems Laboratory. CNS.
    Ghodsi, Ali
    RISE, Swedish ICT, SICS, Computer Systems Laboratory. CNS.
    Haridi, Seif
    RISE, Swedish ICT, SICS, Computer Systems Laboratory. CNS.
    Dealing with Network Partitions in Structured Overlay Networks2009In: Journal of Peer-to-Peer Networking and Applications (PPNA)Article in journal (Refereed)
  • 20898.
    Shafaat, Tallat M.
    et al.
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Ghodsi, Ali
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Haridi, Seif
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Handling Network Partitions and Mergers in Structured Overlay Networks2007Conference paper (Refereed)
    Abstract [en]

    Structured overlay networks form a major class of peer-to-peer systems, which are touted for their abilities to scale, tolerate failures, and self-manage. Any long-lived Internet-scale distributed system is destined to face network partitions. Although the problem of network partitions and mergers is highly related to fault-tolerance and self-management in large-scale systems, it has hardly been studied in the context of structured peer-to-peer systems. These systems have mainly been studied under churn (frequent joins/failures), which as a side effect solves the problem of network partitions, as it is similar to massive node failures. Yet, the crucial aspect of network mergers has been ignored. In fact, it has been claimed that ring-based structured overlay networks, which constitute the majority of the structured overlays, are intrinsically ill-suited for merging rings. In this paper, we present an algorithm for merging multiple similar ring-based overlays when the underlying network merges. We examine the solution in dynamic conditions, showing how our solution is resilient to churn during the merger, something widely believed to be difficult or impossible. We evaluate the algorithm for various scenarios and show that even when falsely detecting a merger, the algorithm quickly terminates and does not clutter the network with many messages. The algorithm is flexible as the tradeoff between message complexity and time complexity can be adjusted by a parameter.

    Download full text (pdf)
    fulltext
  • 20899.
    Shafaat, Tallat M.
    et al.
    RISE, Swedish ICT, SICS. CNS.
    Ghodsi, Ali
    RISE, Swedish ICT, SICS. CNS.
    Haridi, Seif
    RISE, Swedish ICT, SICS. CNS.
    Managing Network Partitions in Structured P2P Networks2009In: Handbook of Peer-to-Peer Networking, Springer , 2009, 6, p. 1127-1148Chapter in book (Refereed)
  • 20900.
    Shafagh, Hossein
    et al.
    ETH Zurich, Switzerland.
    Burkhalter, Lukas
    Hithnawi, Anwar
    ETH Zurich, Switzerland.
    Duquennoy, Simon
    RISE - Research Institutes of Sweden, ICT, SICS. Inria, France.
    Towards Blockchain-based Auditable Storage and Sharing of IoT Data2017In: Proceedings of the International Conference on Cloud Computing Security Workshop (ACM CCSW 2017), November 3, 2017, Dallas, Texas, USA, 2017, p. 45-50Conference paper (Refereed)
415416417418419420421 20851 - 20900 of 26184
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf