Ändra sökning
Avgränsa sökresultatet
6789101112 401 - 450 av 3142
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Träffar per sida
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
Markera
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 401.
    Caster, Ola
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Quantitative methods to support drug benefit-risk assessment2014Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Joint evaluation of drugs’ beneficial and adverse effects is required in many situations, in particular to inform decisions on initial or sustained marketing of drugs, or to guide the treatment of individual patients. This synthesis, known as benefit-risk assessment, is without doubt important: timely decisions supported by transparent and sound assessments can reduce mortality and morbidity in potentially large groups of patients. At the same time, it can be hugely complex: drug effects are generally disparate in nature and likelihood, and the information that needs to be processed is diverse, uncertain, deficient, or even unavailable. Hence there is a clear need for methods that can reliably and efficiently support the benefit-risk assessment process. For already marketed drugs, this process often starts with the detection of previously unknown risks that are subsequently integrated with all other relevant information for joint analysis.

    In this thesis, quantitative methods are devised to support different aspects of drug benefit-risk assessment, and the practical usefulness of these methods is demonstrated in clinically relevant case studies. Shrinkage regression is adapted and implemented for large-scale screening in collections of individual case reports, leading to the discovery of a link between methylprednisolone and hepatotoxicity. This adverse effect is then considered as part of a complete benefit-risk assessment of methylpredniso­lone in multiple sclerosis relapses, set in a general framework of probabilistic decision analysis. Two methods devised in the thesis substantively contribute to this assessment: one for efficient generation of utility distributions for the considered clinical outcomes, driven by modelling of qualitative information; and one for computing risk limits for rare and otherwise non-quantifiable adverse effects, based on collections of individual case reports.

  • 402.
    Caster, Ola
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap. Uppsala Monitoring Centre, Sweden.
    Conforti, Anita
    Viola, Ermelinda
    Edwards, I. Ralph
    Methylprednisolone-induced hepatotoxicity: experiences from global adverse drug reaction surveillance2014Ingår i: European Journal of Clinical Pharmacology, ISSN 0031-6970, E-ISSN 1432-1041, Vol. 70, nr 4, s. 501-503Artikel i tidskrift (Refereegranskat)
  • 403.
    Caster, Ola
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap. Uppsala Monitoring Centre (UMC), Sweden.
    Edwards, I. Ralph
    Comparative Quantitative Benefit-Risk Assessment of High- and Low-Dose Methylprednisolone in Multiple Sclerosis Relapse Management2014Ingår i: Pharmacoepidemiology and Drug Safety, ISSN 1053-8569, E-ISSN 1099-1557, Vol. 23, s. 238-238Artikel i tidskrift (Övrigt vetenskapligt)
  • 404.
    Caster, Ola
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap. Uppsala Monitoring Centre (UMC), Sweden.
    Edwards, I. Ralph
    Quantitative benefit-risk assessment of methylprednisolone in multiple sclerosis relapses2015Ingår i: BMC Neurology, ISSN 1471-2377, E-ISSN 1471-2377, Vol. 15, artikel-id 206Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: High-dose short-term methylprednisolone is the recommended treatment in the management of multiple sclerosis relapses, although it has been suggested that lower doses may be equally effective. Also, glucocorticoids are associated with multiple and often dose-dependent adverse effects. This quantitative benefit-risk assessment compares high-and low-dose methylprednisolone (at least 2000 mg and less than 1000 mg, respectively, during at most 31 days) and a no treatment alternative, with the aim of determining which regimen, if any, is preferable in multiple sclerosis relapses. Methods: An overall framework of probabilistic decision analysis was applied, combining data from different sources. Effectiveness as well as risk of non-serious adverse effects were estimated from published clinical trials. However, as these trials recorded very few serious adverse effects, risk intervals for the latter were derived from individual case reports together with a range of plausible distributions. Probabilistic modelling driven by logically implied or clinically well motivated qualitative relations was used to derive utility distributions. Results: Low-dose methylprednisolone was not a supported option in this assessment; there was, however, only limited data available for this treatment alternative. High-dose methylprednisolone and the no treatment alternative interchanged as most preferred, contingent on the risk distributions applied for serious adverse effects, the assumed level of risk aversiveness in the patient population, and the relapse severity. Conclusions: The data presently available do not support a change of current treatment recommendations. There are strong incentives for further clinical research to reduce the uncertainty surrounding the effectiveness and the risks associated with methylprednisolone in multiple sclerosis relapses; this would enable better informed and more precise treatment recommendations in the future.

  • 405.
    Caster, Ola
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap. Uppsala Monitoring Centre, Sweden.
    Ekenberg, Love
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Combining Second-Order Belief Distributions with Qualitative Statements in Decision Analysis2012Ingår i: Managing Safety of Heterogeneous Systems: Decisions under Uncertainties and Risks / [ed] Yuri Ermoliev, Marek Makowski, Kurt Marti, Springer Berlin/Heidelberg, 2012, s. 67-87Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    There is often a need to allow for imprecise statements in real-world decision analysis. Joint modeling of intervals and qualitative statements as constraint sets is one important approach to solving this problem, with the advantage that both probabilities and utilities can be handled. However, a major limitation with interval-based approaches is that aggregated quantities such as expected utilities also become intervals, which often hinders efficient discrimination. The discriminative power can be increased by utilizing second-order information in the form of belief distributions, and this paper demonstrates how qualitative relations between variables can be incorporated into such a framework. The general case with arbitrary distributions is described first, and then a computationally efficient simulation algorithm is presented for a relevant sub-class of analyses. By allowing qualitative relations, our approach preserves the ability of interval-based methods to be deliberately imprecise. At the same time, the use of belief distributions allows more efficient discrimination, and it provides a semantically clear interpretation of the resulting beliefs within a probabilistic framework.

  • 406.
    Caster, Ola
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap. Uppsala Monitoring Centre (UMC), Sweden.
    Juhlin, Kristina
    Watson, Sarah
    Norén, G. Niklas
    Stockholms universitet, Naturvetenskapliga fakulteten, Matematiska institutionen. Uppsala Monitoring Centre (UMC), Sweden.
    A Paradigm Shift for Screening Individual Case Reports: Accounting for Quality and Content2014Ingår i: Pharmacoepidemiology and Drug Safety, ISSN 1053-8569, E-ISSN 1099-1557, Vol. 23, s. 37-37Artikel i tidskrift (Övrigt vetenskapligt)
  • 407.
    Caster, Ola
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap. Uppsala Monitoring Centre, Sweden.
    Juhlin, Kristina
    Watson, Sarah
    Norén, G. Niklas
    Stockholms universitet, Naturvetenskapliga fakulteten, Matematiska institutionen. Uppsala Monitoring Centre, Sweden.
    Improved Statistical Signal Detection in Pharmacovigilance by Combining Multiple Strength-of-Evidence Aspects in vigiRank2014Ingår i: Drug Safety, ISSN 0114-5916, E-ISSN 1179-1942, Vol. 37, nr 8, s. 617-628Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background

    Detection of unknown risks with marketed medicines is key to securing the optimal care of individual patients and to reducing the societal burden from adverse drug reactions. Large collections of individual case reports remain the primary source of information and require effective analytics to guide clinical assessors towards likely drug safety signals. Disproportionality analysis is based solely on aggregate numbers of reports and naively disregards report quality and content. However, these latter features are the very fundament of the ensuing clinical assessment.

    Objective

    Our objective was to develop and evaluate a data-driven screening algorithm for emerging drug safety signals that accounts for report quality and content.

    Methods

    vigiRank is a predictive model for emerging safety signals, here implemented with shrinkage logistic regression to identify predictive variables and estimate their respective contributions. The variables considered for inclusion capture different aspects of strength of evidence, including quality and clinical content of individual reports, as well as trends in time and geographic spread. A reference set of 264 positive controls (historical safety signals from 2003 to 2007) and 5,280 negative controls (pairs of drugs and adverse events not listed in the Summary of Product Characteristics of that drug in 2012) was used for model fitting and evaluation; the latter used fivefold cross-validation to protect against over-fitting. All analyses were performed on a reconstructed version of VigiBase® as of 31 December 2004, at around which time most safety signals in our reference set were emerging.

    Results

    The following aspects of strength of evidence were selected for inclusion into vigiRank: the numbers of informative and recent reports, respectively; disproportional reporting; the number of reports with free-text descriptions of the case; and the geographic spread of reporting. vigiRank offered a statistically significant improvement in area under the receiver operating characteristics curve (AUC) over screening based on the Information Component (IC) and raw numbers of reports, respectively (0.775 vs. 0.736 and 0.707, cross-validated).

    Conclusions

    Accounting for multiple aspects of strength of evidence has clear conceptual and empirical advantages over disproportionality analysis. vigiRank is a first-of-its-kind predictive model to factor in report quality and content in first-pass screening to better meet tomorrow’s post-marketing drug safety surveillance needs.

  • 408.
    Caster, Ola
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap. Uppsala Monitoring Centre, Sweden.
    Norén, G. N.
    Stockholms universitet, Naturvetenskapliga fakulteten, Matematiska institutionen. Uppsala Monitoring Centre, Sweden.
    Madigan, D.
    Bate, A.
    Logistic regression in signal detection: Another Piece Added to the Puzzle2013Ingår i: Clinical Pharmacology and Therapeutics, ISSN 0009-9236, E-ISSN 1532-6535, Vol. 94, nr 3, s. 312-312Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    To the Editor: In their article, “Performance of Pharmacovigilance Signal-Detection Algorithms for the FDA Adverse Event Reporting System,” Harpaz et al.1 report an evaluation of signal-detection algorithms for spontaneous reports in the US Food and Drug Administration Adverse Event Reporting System against a benchmark constructed by the Observational Medical Outcomes Partnership.

  • 409.
    Caster, Ola
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap. Uppsala Monitoring Centre, Sweden.
    Norén, G. Niklas
    Stockholms universitet, Naturvetenskapliga fakulteten, Matematiska institutionen. Uppsala Monitoring Centre, Sweden.
    Edwards, I. Ralph
    Computing limits on medicine risks based on collections of individual case reports2014Ingår i: Theoretical Biology Medical Modelling, ISSN 1742-4682, E-ISSN 1742-4682, Vol. 11, artikel-id 15Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Quantifying a medicine's risks for adverse effects is crucial in assessing its value as a therapeutic agent. Rare adverse effects are often not detected until after the medicine is marketed and used in large and heterogeneous patient populations, and risk quantification is even more difficult. While individual case reports of suspected harm from medicines are instrumental in the detection of previously unknown adverse effects, they are currently not used for risk quantification. The aim of this article is to demonstrate how and when limits on medicine risks can be computed from collections of individual case reports. Methods: We propose a model where drug exposures in the real world may be followed by adverse episodes, each containing one or several adverse effects. Any adverse episode can be reported at most once, and each report corresponds to a single adverse episode. Based on this model, we derive upper and lower limits for the per-exposure risk of an adverse effect for a given drug. Results: An upper limit for the per-exposure risk of the adverse effect Y for a given drug X is provided by the reporting ratio of X together with Y relative to all reports on X, under two assumptions: (i) the average number of adverse episodes following exposure to X is one or less; and (ii) adverse episodes that follow X and contain Y are more frequently reported than adverse episodes in general that follow X. Further, a lower risk limit is provided by dividing the number of reports on X together with Y by the total number of exposures to X, under the assumption that exposures to X that are followed by Y generate on average at most one report on X together with Y. Using real data, limits for the narcolepsy risk following Pandemrix vaccination and the risk of coeliac disease following antihypertensive treatment were computed and found to conform to reference risk values from epidemiological studies. Conclusions: Our framework enables quantification of medicine risks in situations where this is otherwise difficult or impossible. It has wide applicability, but should be particularly useful in structured benefit-risk assessments that include rare adverse effects.

  • 410.
    Caster, Ola
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap. Uppsala Monitoring Centre, Sweden.
    Norén, G. Niklas
    Stockholms universitet, Naturvetenskapliga fakulteten, Matematiska institutionen. Uppsala Monitoring Centre, Sweden.
    Ekenberg, Love
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Edwards, I. Ralph
    Quantitative Benefit-Risk Assessment Using Only Qualitative Information on Utilities2012Ingår i: Medical decision making, ISSN 0272-989X, E-ISSN 1552-681X, Vol. 32, nr 6, s. E1-E15Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Utilities of pertinent clinical outcomes are crucial variables for assessing the benefits and risks of drugs, but numerical data on utilities may be unreliable or altogether missing. We propose a method to incorporate qualitative information into a probabilistic decision analysis framework for quantitative benefit-risk assessment. Objective: To investigate whether conclusive results can be obtained when the only source of discriminating information on utilities is widely agreed upon qualitative relations, for example, ''sepsis is worse than transient headache'' or ''alleviation of disease is better without than with complications.'' Method: We used the structure and probabilities of 3 published models that were originally evaluated based on the standard metric of quality-adjusted life years (QALYs): terfenadine versus chlorpheniramine for the treatment of allergic rhinitis, MCV4 vaccination against meningococcal disease, and alosetron for irritable bowel syndrome. For each model, we identified clinically straightforward qualitative relations among the outcomes. Using Monte Carlo simulations, the resulting utility distributions were then combined with the previously specified probabilities, and the rate of preference in terms of expected utility was determined for each alternative. Results: Our approach conclusively favored MCV4 vaccination, and it was concordant with the QALY assessments for the MCV4 and terfenadine versus chlorpheniramine case studies. For alosetron, we found a possible unfavorable benefit-risk balance for highly risk-averse patients not identified in the original analysis. Conclusion: Incorporation of widely agreed upon qualitative information into quantitative benefit-risk assessment can provide for conclusive results. The methods presented should prove useful in both population and individual-level assessments, especially when numerical utility data are missing or unreliable, and constraints on time or money preclude its collection.

  • 411.
    Caster, Ola
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap. WHO Collaborating Centre for International Drug Monitoring, Sweden.
    Norén, G. Niklas
    Stockholms universitet, Naturvetenskapliga fakulteten, Matematiska institutionen. WHO Collaborating Centre for International Drug Monitoring, Sweden.
    Madigan, David
    Bate, Andrew
    Large-scale regression-based pattern discovery: The example of screening the WHO global drug safety database2010Ingår i: Statistical Analysis and Data Mining, ISSN 1932-1864, E-ISSN 1932-1872, Vol. 3, nr 4, s. 197-208Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Most measures of interestingness for patterns of co-occurring events are based on data projections onto contingency tables for the events of primary interest. As an alternative, this article presents the first implementation of shrinkage logistic regression for large-scale pattern discovery, with an evaluation of its usefulness in real-world binary transaction data. Regression accounts for the impact of other covariates that may confound or otherwise distort associations. The application considered is international adverse drug reaction (ADR) surveillance, in which large collections of reports on suspected ADRs are screened for interesting reporting patterns worthy of clinical follow-up. Our results show that regression-based pattern discovery does offer practical advantages. Specifically it can eliminate false positives and false negatives due to other covariates. Furthermore, it identifies some established drug safety issues earlier than a measure based on contingency tables. While regression offers clear conceptual advantages, our results suggest that methods based on contingency tables will continue to play a key role in ADR surveillance, for two reasons: the failure of regression to identify some established drug safety concerns as early as the currently used measures, and the relative lack of transparency of the procedure to estimate the regression coefficients. This suggests shrinkage regression should be used in parallel to existing measures of interestingness in ADR surveillance and other large-scale pattern discovery applications.

  • 412.
    Caster, Ola
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap. Uppsala Monitoring Centre, WHO Collaborating Centre for International Drug Monitoring, Sweden.
    Sandberg, Lovisa
    Bergvall, Tomas
    Watson, Sarah
    Noren, G. Niklas
    vigiRank for statistical signal detection in pharmacovigilance: First results from prospective real-world use2017Ingår i: Pharmacoepidemiology and Drug Safety, ISSN 1053-8569, E-ISSN 1099-1557, Vol. 26, nr 8, s. 1006-1010Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Purpose: vigiRank is a data-driven predictive model for emerging safety signals. In addition to disproportionate reporting patterns, it also accounts for the completeness, recency, and geographic spread of individual case reporting, as well as the availability of case narratives. Previous retrospective analysis suggested that vigiRank performed better than disproportionality analysis alone. The purpose of the present analysis was to evaluate its prospective performance. Methods: The evaluation of vigiRank was based on real-world signal detection in VigiBase. In May 2014, vigiRank scores were computed for pairs of new drugs and WHO Adverse Reaction Terminology critical terms with at most 30 reports from at least 2 countries. Initial manual assessments were performed in order of descending score, selecting a subset of drug-adverse drug reaction pairs for in-depth expert assessment. The primary performance metric was the proportion of initial assessments that were decided signals during in-depth assessment. As comparator, the historical performance for disproportionality-guided signal detection in VigiBase was computed from a corresponding cohort of drug-adverse drug reaction pairs assessed between 2009 and 2013. During this period, the requirement for initial manual assessment was a positive lower endpoint of the 95% credibility interval of the Information Component measure of disproportionality, observed for the first time. Results: 194 initial assessments suggested by vigiRank's ordering eventually resulted in 6 (3.1%) signals. Disproportionality analysis yielded 19 signals from 1592 initial assessments (1.2%; P <.05). Conclusions: Combining multiple strength-of-evidence aspects as in vigiRank significantly outperformed disproportionality analysis alone in real-world pharmacovigilance signal detection, for VigiBase.

  • 413.
    Cerratto Pargman, Teresa
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Nouri, Jalal
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Milrad, Marcelo
    Taking an instrumental genesis lens: New insights into collaborative mobile learning2018Ingår i: British Journal of Educational Technology, ISSN 0007-1013, E-ISSN 1467-8535, Vol. 49, nr 2, s. 219-234Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, we argue that in order to gain a deeper understanding of collaborative mobile learning in schools, it is important to know not only how mobile devices affect collaborative learning but also how collaborative learning emerges and is mediated by these devices. We develop our argument by applying the instrumental genesis theory and the collective instrumented activities and situations model for the analysis of learners' collaborative learning in the tablet-mediated classroom. This analysis is grounded in data collected in four elementary Swedish schools (ie, from fourth to eighth grade). From the data, we considered the learners' conversation in English as a foreign language, inquiry-based learning in the natural sciences classroom and game-based learning in the arithmetic classroom. On the one hand, the scrutiny of these specific activities led us to distinguish the pragmatic, epistemic, and reflexive instrumental mediations that have already been theorized in the instrumental genesis theory. On the other hand, they helped us to identify two additional ones, which we call emotional and spatial. Based on these findings, we claim that collaboration in the tablet-mediated classroom is a complex activity that emerges from a variety of instrumental mediations that configure contemporary collaborative mobile learning.

  • 414.
    Cerratto-Pargman, Teresa
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Cerratto-Pargman (2014). A European strand of Sustainable HCI?2014Ingår i: NORDICHI 2014, ACM Press , 2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper reflects onthe topic of the workshopfrom what I have learnedduring a visit atThe Center For Research in Sustainability, Collapse-Preparedness and Information Technology (RISCIT), University of California Irvine, and from a study conducted at a Swedish ecovillage. From these experiences, Ilook forward to contributing to the discussion about a European strand of Sustainable HCI research

  • 415.
    Cerratto-Pargman, Teresa
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Pour une conception des technologies centrée sur l'activité du sujet: le cas de l'écriture de groupe avec collecticiel2006Ingår i: Modèles du sujet pour la conception: dialectiques activités développement / [ed] Pierre Rabardel, Pierre Pastré, Toulouse: Octarès , 2006, s. 157-188Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 416.
    Cerratto-Pargman, Teresa
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    The concept of tool mediation: viewed from the Instrumental Genesis Approach2011Övrigt (Övrig (populärvetenskap, debatt, mm))
  • 417.
    Cerratto-Pargman, Teresa
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    The use of synchronous text-based environments for teacher professional development2001Ingår i: Chat-Kommunikation: Sprache, Interaktion, Sozialität & Identität in synchroner computervermittelter kommunikation: Perspektiven auf ein interdisziplinäres Forschungsfeld / [ed] Michael Beisswenger, Stuttgart: Ibidem-Verlag, 2001Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 418.
    Cerratto-Pargman, Teresa
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    jahnke, isa
    Umeå universitet, , .
    #TMCL15 Changing Teaching and Learning Practices in Schools with Tablet-Mediated Collaborative Learning: Nordic, European and International Views2015Ingår i: Computer Supported Collaborative Learning, International Society of the Learning Sciences , 2015Konferensbidrag (Refereegranskat)
  • 419.
    Cerratto-Pargman, Teresa
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Jahnke, Isa
    Damsa, Crina
    Nussbaum, Miguel
    Säljö, Roger
    Emergent Practices and Material Conditions in Tablet-mediated Collaborative Learning and Teaching2017Ingår i: Making a Difference: Prioritizing Equity and Access in CSCL: 12th International Conference on Computer Supported Collaborative Learning (CSCL) 2017, Volume 2 / [ed] Brian K. Smith, Marcela Borge, Emma Mercier, Kyu Yon Lim, International Society of the Learning Sciences, 2017, s. 905-908Konferensbidrag (Refereegranskat)
    Abstract [en]

    The way in which digital technologies take part and contribute to configuring teaching and collaborative learning practices has become a timely research matter in our field. Current studies in the CSCL field, and particularly on the use of tablets in education, draw attention to how everyday educational practices are entangled with contemporary technologies and, how these technologies shape in turn such practices, in schools and higher education. This half-day workshop aims specifically at accounting for emergent practices in tablet-mediated collaborative learning and teaching, with a particularly focus on the material conditions that constitute such practices. The workshop invites researchers, designers and practitioners to contribute and engage with in-depth analyses of the use of tablets in everyday teaching and learning, in schools and higher education contexts. Furthermore, the workshop intends to trigger and facilitate participants to generate/propose conceptual and methodological analytical tools for examining the material conditions of tablet-mediated collaborative learning and teaching practices. The outcomes of the workshop will consist of (1) a repertoire of (identified) emergent practices bounded to the use of tablets in schools and higher education, reported by the participants, (2) a set of conceptual and analytical tools for the study of material conditions of CSCL practices and (3) a network bringing together researchers, practitioners and designers to set up a research agenda and initiate a consortium including the organisation of a special issue in an International journal.

  • 420.
    Cerratto-Pargman, Teresa
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Joshi, Somya
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Reconfiguring civic participation: open source software in the political space2016Konferensbidrag (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    Discourses on participation, democracy and politics are today profoundly questioned and challenged. Internet and the entrance of open source software into the governmental sphere have much contributed toward the shift in understandings of citizen participation, their rights and representation. In the field of participatory design such an inquiry is reflected in a shift of focus regarding the study of the use of technologies within government. From being concerned by issues on transparency and equity researchers are nowadays more prone to explore issues regarding the transformative power or/and performativity of open source software in contexts such as government. This paper describes the case of the political “Net Party” which in 2013 introduced the platform “Democracy OS” into the legislature of the Ciudad de Buenos Aires in Argentina. The question that motivates the study is: Do open source tools redefine the political space and reconfigure citizen civic participation? And if so, how? The paper contributes five analytical axes for scrutinizing the entrance of open source tools into the political space.

  • 421.
    Cerratto-Pargman, Teresa
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Joshi, Somya
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Understanding Limits from a Social-Ecological perspective2015Ingår i: First Monday, ISSN 1396-0466, E-ISSN 1396-0466, Vol. 20, nr 8Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The latest developments in the field of HCI have given rise to an increasing interest in issues pertaining to global warming, resource depletion and environmental degradation. Concern about such issues has contributed to give shape to the design space of sustainable HCI (SHCI); a space whose boundaries are at times blurred. On the one hand, some, design “sustainable” information technology based on visions of the world that do not really question limits to continuous economic growth and, on the other hand, others embrace the design of information technology from stances that acknowledges limits (i.e., economic, ecological, energetic). This paper introduces the perspective of social ecology into SHCI. This perspective provides us with a core set of principles that makes us situate computing at the intersection of physical (natural) and moral (human) qualities of our human environment systems. As such it confronts us with choices to be made in the challenging years to come and invites us to argue about the very purpose of information technology in a world of limitations.

  • 422.
    Cerratto-Pargman, Teresa
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Järvela, Sanna M.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Milrad, Marcelo
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Designing Nordic Technology-enhanced Learning2012Ingår i: The Internet and higher education, ISSN 1096-7516, E-ISSN 1873-5525, Vol. 15, nr 4, s. 227-230Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The latest developments of information and communication technologies (ICT) and its large penetration in different sectors of our society pose new challenges and demands in the field of education. This special issue entitled "Designing Nordic technology-enhanced learning (TEL)", presents and discusses how researchers in the Nordic countries are currently framing and thinking about issues that are related to pedagogical design of learning spaces, digital literacies, educational professional development, design of tools engaging students in collaborative inquiry learning as well as design-oriented multimodal understandings of learning. The objective pursued with the special issue has been to reflect upon current problems that educational institutions, practitioners and TEL researchers are facing in the Nordic countries as regards the acknowledgment of young people's ICT practices within formal education. Such analytical work has led us to identify and elaborate on what we believe constitute forthcoming research challenges for learning and education in the Nordic countries.

  • 423.
    Cerratto-Pargman, Teresa
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Knutsson, Ola
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Celikten, Emre
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Sneiders, Eriks
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Dalianis, Hercules
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    User Centered Development of Automatic E-mail Answering for the Public Sector2012Ingår i: Human-Computer Interaction, Tourism and Cultural Heritage / [ed] Francisco Cipolla-Ficarra, Kim Veltman, Huang Chih-Fang, Miguel Cipolla-Ficarra, Andreas Kratky, Springer Berlin/Heidelberg, 2012, Vol. 7546, s. 154-156Konferensbidrag (Refereegranskat)
    Abstract [en]

    In Sweden, the use of e-mail by the public sector has become a key communication service between citizens and governmental authorities. Although the integration of e-mail in the public sector has certainly brought citizens and handling officers closer, it has also introduced a particular vision on governmental authorities such as for instance the idea that public service and information should be available to citizens any time, anywhere. Such a belief among citizens puts certainly high demands on the quality and efficiency of the e-service governmental authorities are capable to provide. In fact, the growing number of citizens’ electronic requests must be accurately answered in a limited time. In the research project IMAIL (Intelligent e-mail answering service for eGovernment) [1], we have focused on the work carried out at the Swedish Social Insurance Agency (SSIA) that exemplifies a governmental authority dealing with 500,000 emails per year on top of face-to face meetings, phone calls and chat communication. With the objective of creating an e-mail client capable to ease and ensure the quality of SSIAs’ handling officers public service, we have developed a prototype that: (1) automatically answer a large part of simple questions in the incoming e-mail flow, (2) improve the quality of the semi- automatic answers (i.e. answer templates), and finally, (3) reduce the workload for the handling officers. The development of the prototype is grounded in an empirical study conducted at the SSIA. The study comprises the analysis and clustering of 10,000 citizens e-mails and the working activity of 15 handling officers that were collected through questionnaires, interviews and workshops [2].

  • 424.
    Cerratto-Pargman, Teresa
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Knutsson, Ola
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Daniel, Spikol
    Milrad, Marcelo
    Otero, Nuno
    Ramberg, Robert
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Exploring Teachers’ perspectives on the use of Mobile devices for Math and Language Learning2014Ingår i: Conference proceedings: 4th international Designs for Learning conference 6-9th May 2014, Stockholm: Stockholm University, 2014Konferensbidrag (Refereegranskat)
  • 425.
    Cerratto-Pargman, Teresa
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Knutsson, Ola
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Karlström, Petter
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Materiality of Online Students’ Peer-Review Activities in Higher Education2015Ingår i: Exploring the Material Conditions of Learning: The Computer Supported Collaborative Learning (CSCL) Conference 2015: Conference Proceedings. Volume 1 / [ed] Oskar Lindwall, Päivi Häkkinen, Timothy Koschmann, Pierre Tchounikine, Sten Ludvigsen, International Society of the Learning Sciences, 2015, s. 308-315Konferensbidrag (Refereegranskat)
    Abstract [en]

    In spite of the widespread use of technology in higher education, discourses on learning technologies commonly account for their features as disembodied from their use. There has so far been few theoretical approaches which have delved into "the technology question" in CSCL. We present an empirical study that investigates how students’ peer-review activities are entangled with sociomaterial aspects of mediated collaborative learning. The students' peer-review activities were analyzed according to the Collective Instrument-mediated Activity Situation (CIAS) model, and findings show that the materiality of two different tools had considerable influenced how students engaged with the texts and how they interacted with each other.

  • 426.
    Cerratto-Pargman, Teresa
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Knutsson, Ola
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Milrad, Marcelo
    Otero, Nuno
    Ramberg, Robert
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Spikol, Daniel
    Purposeful Learning Across Collaborative Educational Spaces2014Ingår i: 11 th International conference of the learning sciences: proceedings / [ed] Joseph L. Polman et al, New York: International Society of the Learning Sciences , 2014, s. 1597-1598Konferensbidrag (Refereegranskat)
  • 427.
    Cerratto-Pargman, Teresa
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Knutsson, Ola
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Näslund, Anders
    Feldt, Tommy
    The use of social annotations tools in higher education2014Ingår i: Conference proseedings: 4th international Designs for Learning conference 6-9th May 2014, Stockholm: Stockholm University , 2014Konferensbidrag (Refereegranskat)
  • 428.
    Cerratto-Pargman, Teresa
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Milrad, Marcelo
    Beyond Innovation in Mobile Learning: towards Sustainability in Schools2016Ingår i: Mobile learning: the next generation / [ed] John Traxler, Agnes Kukulska-Hulme, New York: Routledge, 2016, s. 154-178Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 429.
    Cerratto-Pargman, Teresa
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Milrad, Marcelo
    Linnaeus university, , .
    Järvela, Sanna
    Oulu University, , .
    A Scandinavian Perspective on Technology-Enhanced Learning2011Konferensbidrag (Refereegranskat)
  • 430.
    Cerratto-Pargman, Teresa
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Nouri, Jalal
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    One Tablet, Multiple Epistemic Instruments in the Everyday Classroom2017Ingår i: Data Driven Approaches in Digital Education: Proceedings / [ed] Élise Lavoué, Hendrik Drachsler, Katrien Verbert, Julien Broisin, Mar Pérez-Sanagustín, Springer, 2017, s. 379-384Konferensbidrag (Refereegranskat)
    Abstract [en]

    Grounded in the analyses of 23 semi-structured interviews and 31 field notes from classroom observations, this study scrutinizes the relationships that teachers and learners entertain with/through the tablet in their process of technology appropriation in the classroom. The results reveal that, on the one hand, the learners elaborate a variety of instruments from their interactions with the tablet and, on the other hand, that the teachers’ appropriation plays a central role in configuring a creative, critical and participatory pedagogy in the contemporary classroom.

  • 431.
    Cerratto-Pargman, Teresa
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Nouri, Jalal
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Tablets in the CSCL Classroom: A Lens on Teachers’ Instrumental Geneses2017Ingår i: Making a Difference: Prioritizing Equity and Access in CSCL: 12th International Conference on Computer Supported Collaborative Learning (CSCL) 2017 / [ed] Brian K. Smith, Marcela Borge, Emma Mercier, Kyu Yon Lim, International Society of the Learning Sciences, 2017, Vol. 2, s. 837-838Konferensbidrag (Refereegranskat)
  • 432.
    Cerratto-Pargman, Teresa
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Nouri, Jalal
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Tablets in the CSCL Classroom: A Lens on Teachers’ Instrumental Geneses2017Ingår i: Making a Difference: Prioritizing Equity and Access in CSCL: 12th International Conference on Computer Supported Collaborative Learning (CSCL) 2017, Volume 2 / [ed] Brian K. Smith, Marcela Borge, Emma Mercier, Kyu Yon Lim, International Society of the Learning Sciences, 2017, s. 837-838Konferensbidrag (Refereegranskat)
    Abstract [en]

    Most educational research on tablets in schools seeks to find out whether children learn more efficiently with or without such devices. This study differs from such research as it instead investigates how tablets take part in the everyday CSCL classroom? Grounded in the instrumental genesis theory, this study focuses on the multifarious relationships between teacher-tablets-learner(s) to inform the processes of tablet appropriation in the classroom. Analysis of the instrumental processes observed reveals that learners on the one hand develop usage schemes that challenge those developed by the teachers. Teachers on the other hand are forced to review their competence, rethinking power-relationships vis-à-vis learners and have to reflect/design a creative, critical and participatory pedagogical practice that is aligned with learners’ utilization schemes and the instruments they bring to our contemporary classrooms.

  • 433.
    Cerratto-Pargman, Teresa
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Pargman, Daniel
    Nardi, Bonnie
    The Internet at the eco-village: Performing Sustainability in the twenty-first century2016Ingår i: First Monday, ISSN 1396-0466, E-ISSN 1396-0466, Vol. 21, nr 5Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Is the digital infrastructure and its footprint an ideological blind spot for recently emerging ecological communities, including eco-villages? This paper examines how a group of people who are concerned with environmental issues such as peak oil and climate change are orchestrating a transition toward a more sustainable and resilient way of living. We studied a Swedish eco-village, considering how computing in this community contributes to defining what alternative ways of living might look like in the twenty-first century. Drawing on a social-ecological perspective, the analysis illustrates, on the one hand, that the Internet, along with the digital devices we use to access it, capitalizes and mobilizes values, knowledge and social relationships that in turn enhance resilience in the eco-village. On the other hand, the analysis shows that an explicit focus on ecological values is not sufficient for a community of individuals to significantly transform Internet use to conform to ecological ideals. This work contributes to a deeper understanding of the imbrication of social technologies with practices that are oriented to perform sustainable and resilient ways of living.

  • 434.
    Cerratto-Pargman, Teresa
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Rossitto, Chiara
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Barkhuus, Louise
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Understanding Audience Participation in Interactive Theater Performances2014Ingår i: Proceeding NordiCHI '14 Proceedings of the 8th Nordic Conference on Human-Computer Interaction: fun, Fast, Foundational, New York: ACM Press, 2014, s. 608-617Konferensbidrag (Refereegranskat)
    Abstract [en]

    This article presents an empirical study investigating audience participation in an interactive theater performance. During the performance, audience members were enticed to act upon and contribute to the performance by sharing their opinions, emotions, values and other thoughts, by means of text messages that were integrated into the performance itself. The study aimed at understanding the main characteristics of audience participation in the interactive performance, as well as the role of communication technology as a medium enabling social participation. The results draw attention to the immediate and reflective facets of audience participation, both unfolding at two different but interrelated levels of interactions: an individual and collective one.

  • 435. Chalmers, Matthew
    et al.
    Dieberger, Andreas
    Höök, Kristina
    Rudström, Åsa
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Social Navigation and Seamful Design2004Ingår i: Journal of the Japanese Cognitive Science Society, Vol. 11, nr 3, s. 171-181Artikel i tidskrift (Refereegranskat)
  • 436.
    Chalmers, Matthew
    et al.
    University of Glasgow, School of Computing Science, .
    McMillan, Donald
    University of Glasgow, School of Computing Science, .
    Morrison, Alistair
    University of Glasgow, School of Computing Science, .
    Cramer, Henriette
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Rost, Mattias
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Mackay, Wendy
    Université de Paris Sud, , .
    Ethics, Logs and Videotape: Ethics in Large Scale User Trials and User Generated Content2011Ingår i: CHI '11 CHI Conference on Human Factors in Computing Systems Vancouver, BC, Canada — May 07 - 12, 2011, Vancouver, Canada: ACM Press , 2011Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    As new technologies are appropriated by researchers, the community must come to terms with the evolving ethical responsibilities we have towards participants. This workshop brings together researchers to discuss the ethical issues of running large-scale user trials, and to provide guidance for future research. Trials of the scale of 10s or 100s of thousands of participants offer great potential benefits in terms of attracting users from vastly different geographical and social contexts, but raise significant ethical challenges. The inability to ensure user understanding of the information required to provide informed consent and problems involved in making users aware of the implications of the information being collected all beg the question: how can researchers ethically take advantage of the opportunities these new technologies afford?

  • 437. Chandler, Rebecca E.
    et al.
    Juhlin, Kristina
    Fransson, Jonas
    Caster, Ola
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap. Uppsala Monitoring Centre, WHO Collaborating Centre for International Drug Monitoring, Sweden.
    Edwards, I. Ralph
    Norén, G. Niklas
    Current Safety Concerns with Human Papillomavirus Vaccine: A Cluster Analysis of Reports in VigiBase (R)2017Ingår i: Drug Safety, ISSN 0114-5916, E-ISSN 1179-1942, Vol. 40, nr 1, s. 81-90Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Introduction A number of safety signals-complex regional pain syndrome (CRPS), postural orthostatic tachycardia syndrome (POTS), and chronic fatigue syndrome (CFS)-have emerged with human papillomavirus (HPV) vaccines, which share a similar pattern of symptomatology. Previous signal evaluations and epidemiological studies have largely relied on traditional methodologies and signals have been considered individually. Objective The aim of this study was to explore global reporting patterns for HPV vaccine for subgroups of reports with similar adverse event (AE) profiles. Methods All individual case safety reports (reports) for HPV vaccines in VigiBase (R) until 1 January 2015 were identified. A statistical cluster analysis algorithm was used to identify natural groupings based on AE profiles in a data-driven exploratory analysis. Clinical assessment of the clusters was performed to identify clusters relevant to current safety concerns. Results Overall, 54 clusters containing at least five reports were identified. The four largest clusters included 71 % of the analysed HPV reports and described AEs included in the product label. Four smaller clusters were identified to include case reports relevant to ongoing safety concerns (total of 694 cases). In all four of these clusters, the most commonly reported AE terms were headache and dizziness and fatigue or syncope; three of these four AE terms were reported in >50 % of the reports included in the clusters. These clusters had a higher proportion of serious cases compared with HPV reports overall (44-89 % in the clusters compared with 24 %). Furthermore, only a minority of reports included in these clusters included AE terms of diagnoses to explain these symptoms. Using proportional reporting ratios, the combination of headache and dizziness with either fatigue or syncope was found to be more commonly reported in HPV vaccine reports compared with non-HPV vaccine reports for females aged 9-25 years. This disproportionality remained when results were stratified by age and when those countries reporting the signals of CRPS (Japan) and POTS (Denmark) were excluded. Conclusions Cluster analysis reveals additional reports of AEs following HPV vaccination that are serious in nature and describe symptoms that overlap those reported in cases from the recent safety signals (POTS, CRPS, and CFS), but which do not report explicit diagnoses. While the causal association between HPV vaccination and these AEs remains uncertain, more extensive analyses of spontaneous reports can better identify the relevant case series for thorough signal evaluation.

  • 438. Chang, C-C
    et al.
    Nagel, D. J.
    Muftic, Sead
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Balancing Security and Energy Consumption in Wireless Sensor Networks2007Ingår i: Proceedings 3rd International Conference on Mobile Ad-hoc and Sensor Networks (MSN 2007) / [ed] Hongke Zhang et al., Berlin/Heidelberg: Springer , 2007, s. 469-480Konferensbidrag (Refereegranskat)
    Abstract [en]

    Appling security to messages traveling over wireless links in sensor nodes requires additional energy. This paper describes our suggestions on balancing the level of security and energy consumption based on our measurements using CrossBow and Ember sensor nodes. It was found that the node microcontroller's CPU operates for substantially longer times for both hashing and encryption operations compared to the time for handling messages without any security. However, this has little overall impact on energy consumption. The longer high-power radio transmission times due to hashing were especially costly. For the full operational mode, with CPU processing and also radio transmission of messages, our results indicate that the lifetime of a transmitting node in a security regime is only about one-half of the lifetime without security. Hence, we provided design guidelines to apply security with energy consideration for WSN. They include 2 to 8 bytes MACs for integrity and authentication instead of SHA-1, and the size of messages should match the steps of encryption algorithms.

  • 439. Chang, Chih-Chun
    et al.
    Arafa, Shadi
    Muftic, Sead
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Key Establishment Protocol for Wireless Sensor Networks2007Ingår i: Global and Homeland Security (MASS-GHS 2007), IEE , 2007, s. 1-6Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper describes the design, prototype implementation and deployment of a key management protocol for sensor networks. In order to exchange protected messages between sensor nodes in a wireless sensor network, secret shared cryptographic keys must be established between the nodes of the network. Several key management schemes have been proposed in the literature, but these schemes are not suitable for real-life deployment. In this paper, we approach the problems of key management protocol differently from other reported results. We first analyzed functionality, feasibility and flexibility of the current key management protocols. Then, we introduce the concept of the Trusted Base Station as the foundation of our new protocol. The results of our implementation and deployment in a real WSN environment show that our theoretical results and claims are supported by the results of practical tests and measurements of operational efficiency.

  • 440. Chang, Chih-Chun
    et al.
    Muftic, Sead
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Nagel, David J.
    Measurement of Energy Costs of Security in Wireless Sensor Nodes2007Ingår i: Proceedings - International Conference on Computer Communications and Networks, ICCCN, IEEE , 2007, s. 95-102Konferensbidrag (Refereegranskat)
    Abstract [en]

    Both correct transmission using hashing and protection of messages using encryption in sensor nodes require additional energy. This paper describes our measurement results for energy consumption in CrossBow and Ember sensor nodes for the process of exchanging data messages between nodes both in the clear and in a protected form. Full strength algorithms were loaded into and executed in nodes. It was found that the CPU operates for substantially longer times for both hashing and encryption operations compared to the time for handling messages without any security. The longer radio transmission times due to hashing were especially costly. Hence, security algorithms have great impacts on energy consumption in sensor nodes. For the full operational mode, with CPU processing and also radio transmission of messages, our results indicate that the lifetime of a transmitting node in a security regime is only about onehalf of the lifetime without security.

  • 441. Chang, Chih-Chun
    et al.
    Nagel, D. J.
    Muftic, Sead
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Assessment of Energy Consumption in Wireless Sensor Networks: A Case Study for Security Algorithms2007Ingår i: Proceedings of IEEE International Workshop on Wireless and Sensor Networks Security (IEEE WSNS 2007), IEEE , 2007, s. 1-6Konferensbidrag (Refereegranskat)
    Abstract [en]

    WSN nodes are usually powered by batteries. Energy consumption during node operation determines battery life. Power consumption depends on the different hardware and software components in a WSN node and their various activities. In order to determine the life of the battery, we must measure the energy consumption of a node that is active in a network. That is, we must know the power consumption and time duration for node activities including computations, and RF transmission and reception. In this paper, we introduce an easy and accurate method for dynamic energy measurements without disturbing the node or network. The method consists of an oscilloscope, which can stream digitized voltages into a PC, which calculates the profile of energy consumption. We employed this capability to determine energy consumption for different security algorithms in CrossBow MICA2 nodes.

  • 442. Chapman, Wendy W.
    et al.
    Hilert, Dieter
    Velupillai, Sumithra
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Kvist, Maria
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Skeppstedt, Maria
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Chapman, Brian
    Conway, Michael
    Tharp, Melissa
    Mowery, Danielle L.
    Deleger, Louise
    Extending the NegEx Lexicon for Multiple Languages2013Ingår i: Proceedings of the 14th World Congress on Medical and Health Informatics / [ed] Christoph Ulrich Lehmann, Elske Ammenwerth, Christian Nøhr, IOS Press, 2013, Vol. 192, s. 677-681Konferensbidrag (Refereegranskat)
    Abstract [en]

    We translated an existing English negation lexicon (NegEx) to Swedish, French, and German and compared the lexicon on corpora from each language. We observed Zipf’s law for all languages, i.e., a few phrases occur a large number of times, and a large number of phrases occur fewer times. Negation triggers “no” and “not” were common for all languages; however, other triggers varied considerably. The lexicon is available in OWL and RDF format and can be extended to other languages. We discuss the challenges in translating negation triggers to other languages and issues in representing multilingual lexical knowledge.

  • 443.
    Charitakis, Konstantinos
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Using parallel corpora to create a Greek-English dictionary with Uplug2007Ingår i: NODALIDA 2007 PROCEEDINGS / [ed] Joakim Nivre, Heiki-Jaan Kaalep, Kadri Muischnek and Mare Koit, 2007, s. 212-215Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents the construction of a Greek-English bilingual dictionary from parallel corpora that were created manually by collected documents retrieved from the Internet. The parallel corpora processing was performed by the Uplug word alignment system without the use of language specific information. A sample was extracted from the population of suggested translations and was included in questionnaires that were sent out to Greek-English speakers who evaluated the sample based on the quality of the translation pairs. For the suggested translation pairs of the sample belonging to the stratum with the higher frequency of occurrence, 67.11% correct translations were achieved. With an overall 50.63% of correct translations of the sample, the results were promising considering the minimal optimisation of the corpus and the differences between the two lan- guages.

  • 444.
    Chaula, Job Asheri
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    A Socio-technical Analysis of Information Systems Security Assurance: A Case Study for Effective Assurance2006Doktorsavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    This thesis examines the concepts of Information System (IS) security assurance using a socio-technical framework. IS security assurance deals with the problem of estimating how well a particular security system will function efficiently and effectively in a specific operational environment. In such environments, the IS interact with other systems such as ethical, legal, operational and administrative. Security failure in any of these systems may result in security failure of the whole system.

    In this thesis a socio-technical framework is used to examine culture, usability problems, security internal controls, security requirements and re-use of security requirements of TANESCO information systems. TANESCO is the energy utility company in Tanzania where the case study was conducted. Results show that culture affects the way people approach IS security. Also results show that the socio-technical framework is effective in modeling systems security and its environment. The re-use of security requirements is also shown to significantly minimise the time taken when developing and improving security requirements for an IS.

    The overall purpose of this thesis has been to develop a framework for information systems security assurance. The resulting framework of thinking brings together numerous assurance concepts into a coherent explanation that should be useful for any organisation or evaluators seeking to understand the underlying principals of systems security assurance. It contains organisational, cultural, and technical issues that should be looked at when considering and applying systems security assurance methods and techniques.

  • 445.
    Chemane, Lourino
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    ICT Platform Integration - MCDM Based Framework for the Establishment of Value Network: Case Study: Mozambique Government Electronic Network (GovNet)2011Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The selection of ICT service providers are among many of the challenges in building networks (intranets and extensions to the Internet) due to the high investment on equipment (CAPEX) and on operational costs (OPEX). This thesis proposes a Multi-Criteria Decision Method based decision support framework via the deployment of the Analytical Hierarchy Process method that can be used to improve selection and evaluation practices. The work deals explicitly with the role of ICT in supporting the corporate mission, and goals, in building the organization value network. It helps also in planning and defining the access to the Internet and strategies for making critical ICT related decisions. A specific study, The Government Electronic Network Project in Mozambique, has been used as a use case for the developed model and for validating the framework. The thesis also covers aspects related to the broader eGovernment process in Mozambique, such as the architecture, the principles, and the associated IT protocols and standards required for the interoperability of the respective eGovernment systems.

    The framework and recommendations are expected to contribute in assisting organizations to increase the usage and improve the management of IT platforms and services. In addition, they should help in bettering the systematization of the input data in specifying the requirements for the services offered by Internet service providers. The model should bring to the attention of decision-makers many factors that are currently neither considered nor are central to the selection processes. Furthermore, the decision-makers can use the framework in explaining and describing the investment decisions behind ICT projects in the context of the organization value network.

  • 446.
    Chemane, Lourino
    et al.
    UTICT, Mozambique.
    Carrilho, Sérgio
    Ekenberg, Love
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Taula, Rufino
    MCDM Framework and the Selection of Network Topology: GovNet Case Study2006Ingår i: IST-Africa 2006 Conference Proceedings / [ed] Paul Cunningham & Miriam Cunningham, IIMC International Information Management Corporation , 2006Konferensbidrag (Refereegranskat)
  • 447.
    Chemane, Lourino
    et al.
    UTICT, Mozambique.
    Ekenberg, Love
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    e-Government and Architecture Principles Government Portal Case Study2006Ingår i: Exploiting the Knowledge Economy: Issues, Applications, Case Studies / [ed] Paul Cunningham & Miriam Cunningham, Amsterdam: IOS Press , 2006Konferensbidrag (Refereegranskat)
  • 448.
    Chemane, Lourino
    et al.
    UTICT, Mozambique.
    Ekenberg, Love
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Finger, Matthias
    eGovernment and Sociotechnical Feedback Control System2008Ingår i: IST-Africa 2008 Conference Proceedings / [ed] Paul Cunningham & Miriam Cunningham, IIMC International Information Management Corporation , 2008Konferensbidrag (Refereegranskat)
  • 449.
    Chemane, Lourino
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Ekenberg, Love
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Popov, Oliver
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Carrilho, S.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Government Network and Information Security MCDM Framework for the Selection of Security Mechanisms:  2005Ingår i: Proceedings of CNIS 2005 / [ed] M.H. Hamza, Phoenix, USA: Acta Press , 2005Konferensbidrag (Refereegranskat)
    Abstract [en]

    The establishment of Virtual Private Networks (VPNs), Intranets and Internet access channels by Governments raises the need of making sure that only authorized people access the Government VPN resources. The large base of network security mechanisms and VPN implementation alternatives available makes it difficult to select the “optimal” security mechanisms or controls to be used in order to ensure the required or defined level of security for a specific VPN. This paper addresses the security mechanisms selection problem by proposing a MCDM model for structuring the VPN selection decision problem. Data collected from the Government Network Project (GovNet) being implemented in Mozambique was used to support both the development and validation of the Model.

  • 450.
    Chemane, Lourino
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Ekenberg, Love
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Popov, Oliver
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Cossa, T.
    MCDM Model for Selecting Internet Access Technologies: A Case Study in Mozambique2005Ingår i: EUROCON 2005: The International Conference on "Computer as a Tool", Proceedings, volume II, 2005, s. 1738-1741Konferensbidrag (Refereegranskat)
    Abstract [en]

    The development of Internet, networking and access technologies is providing a wide variety of Internet interconnection alternatives. The availability of several options in the Internet interconnection market makes it difficult to select the "optimal" alternative for a specific end-user in a specific context. A MCDM based model for structuring and solving the Internet access technologies selection decision problem is proposed. The applicability and validation of this approach is demonstrated in a case study in Mozambique

6789101112 401 - 450 av 3142
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf