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  • 401.
    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.

  • 402.
    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.

  • 403.
    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.

  • 404.
    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

  • 405.
    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)
  • 406.
    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))
  • 407.
    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)
  • 408.
    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)
  • 409.
    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.

  • 410.
    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.

  • 411.
    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.

  • 412.
    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.

  • 413.
    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].

  • 414.
    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)
  • 415.
    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.

  • 416.
    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)
  • 417.
    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)
  • 418.
    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)
  • 419.
    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)
  • 420.
    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.

  • 421.
    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)
  • 422.
    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.

  • 423.
    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.

  • 424.
    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.

  • 425. 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)
  • 426.
    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?

  • 427. 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.

  • 428. 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.

  • 429. 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.

  • 430. 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.

  • 431. 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.

  • 432. 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.

  • 433.
    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.

  • 434.
    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.

  • 435.
    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.

  • 436.
    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)
  • 437.
    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)
  • 438.
    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)
  • 439.
    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.

  • 440.
    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

  • 441.
    Chemane, Lourino
    et al.
    UTICT, Mozambique.
    Ekenberg, Love
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Popov, Oliver
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Saifodine, Z.
    Government Network and ISP Selection Model - Mozambique Case Study2005Ingår i: Innovation and the Knowledge Economy: Issues, Applications, Case Studies / [ed] Paul Cunningham & Miriam Cunningham, Amsterdam: IOS Press , 2005Konferensbidrag (Refereegranskat)
  • 442.
    Chemane, Lourino
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Mapsanganhe, Sergio
    UTICT.
    GovNet e-Mail System Capacity Planning2007Ingår i: IST-Africa 2007 Conference Proceedings / [ed] Paul Cunningham & Miriam Cunningham, 2007Konferensbidrag (Refereegranskat)
    Abstract [en]

    Electronic Government Network (GovNet) e-Mail System, one of the services offered as part of the GovNet Project in Mozambique is expanding. A significant growth in the number of users of the GovNet e-Mail system is expected in the next couple of months due to the addition of 63 new sites /institutions as part of the GovNet-Extension Project. To address the expected demand on the GovNet IT resources there are scientifically proven methods and processes that can aid the planning of the required networking and IT resources. This paper tries to propose an approach to be followed as part of the process of capacity planning for the GovNet e-Mail System storage and bandwidth capacity. All the data in support of the suggested method were collected during the pilot phase of the GovNet through automatic traffic collection application and through interviews of the IT managers of the government institutions benefiting from the GovNet services.

  • 443.
    Chemane, Lourino
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Taula, Rufino
    Tomas, Joaquim
    Centralized e-Mail System: Government Network Case Study2007Ingår i: IST-Africa 2007 Conference Proceedings / [ed] Paul Cunningham 6 Miriam Cunningham, Maputo-Mozambique: IIMC International Information Management Corporation , 2007Konferensbidrag (Refereegranskat)
    Abstract [en]

    The Mozambique eGovernment Strategy has, as one of its objectives, the use of ICTs to improve the effectiveness and efficiency of the public service delivery.  The achievement of this objective depends on the development and deployment of several information systems, such as the implementation of a centralized and government-wide e-mail system, instant messaging and other common communication services. In this paper we analyse the implications resulting from the current approach of using different Internet Service Providers (ISPs) and disaggregated e-mail systems for e-mail communications between public institutions in Mozambique and we propose another approach to the Government of Mozambique for e-mail communication. The information and data used for the analysis were collected through interviews, questionnaires and GovNet statistics and traffic measurements. The main contribution consisted in applying scientific approach for advising the most appropriate alternative of e-mail system for the Government of Mozambique.

  • 444. Chen, Yihsu
    et al.
    Tanaka, Makoto
    Siddiqui, Afzal S.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap. University College London, United Kingdom.
    Tradable Performance-Based CO₂ Emissions Standards: Walking on Thin Ice?2016Ingår i: Energy: Expectations and Uncertainty: 39th International Conference Proceedings of the International Association for Energy Economics, International Association for Energy Economics , 2016, s. 1-28Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Climate policy, like climate change itself, is subject to debate. Partially due to the political deadlock in Washington, DC, US climate policy, historically, has been driven mainly by state or regional effort until the recently introduced federal Clean Power Plan (CPP). Instead of a traditional mass-based standard, the US CPP stipulates a state-specific performance-based CO2 emission standard and delegates considerable flexibility to the states in achieving the standard. Typically, there are two sets of policy tools available: a tradable performance-based and a mass-based permit program. We analyze these two related but distinct standards when they are subject to imperfect competition in the product and/or permit markets. Stylized models are developed to produce general conclusions. Detailed models that account for heterogenous technologies and the transmission network are developed to evaluate policy efficiency. Depending on the scenarios under consideration, the resulting problem could be either a complementarity problem or a Stackelberg leaderfollower game, which is implemented as a mathematical program with equilibrium constraints (MPEC). We overcome the nonconvexity of MPECs by reformulating them as mixed integer problems. We show that while the cross-subsidy inherent in the performance-based standard that might effectively reduce power prices, it could inflate energy demand, thereby rendering permits scarce. When the leader in a Stackelberg formulation has a relatively clean endowment under the performancebased standard, its ability to manipulate the electricity market as well as to lower permit prices might worsen the market outcomes compared to its mass-based counterpart. On the other hand, when the leader has a relatively dirty endowment, the "cross-subsidy" could be the dominant force leading to a higher social welfare compared to the mass-based program. This paper contributes to the current policy debates in regulating emissions from the US power sector and highlights different incentives created by the mass- and performance-based standards.

  • 445. Chopra, Amit
    et al.
    van der Torre, LeonVerhagen, HarkoStockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.Villata, Serena
    Normative Multi-Agent Systems: Report from Dagstuhl Seminar 151312015Proceedings (redaktörskap) (Refereegranskat)
    Abstract [en]

    This report documents the program and the outcomes of Dagstuhl Seminar 15131 “Normative Multi-Agent Systems”. Normative systems are systems in the behavior of which norms play a role and which need normative concepts in order to be described or specified. A normative multi-agent system combines models for normative systems (dealing for example with obligations, permissions and prohibitions) with models for multi-agent systems. Normative multi-agent systems provide a promising model for human and artificial agent coordination because they integrate norms and individual intelligence. They are a prime example of the use of sociological theories in multi- agent systems, and therefore of the relation between agent theory—both multi-agent systems and autonomous agents—and the social sciences—sociology, philosophy, economics, legal science, etc. The aim of this Dagstuhl Seminar was to feature two fresh themes in broader computing and software engineering: social computing and governance. These themes are highly interdis- ciplinary, bringing together research strands from computing, information sciences, economics, sociology, and psychology. Further there is considerable excitement about these areas in aca- demia, industry, and public policy organizations. Our third theme was agreement technologies, a more traditional topic but nonetheless relevant for the NorMAS community. A norm is a fun- damental social construct. Norms define the essential fabric of a society. Our purpose in this seminar was to explore the connections of norms to each of the themes, especially from a com- putational perspective. Moreover, the seminar has been conceived for the writing of a volume titled “Handbook of Normative Multi Agent Systems” aimed to become a standard reference in the field and to provide guidelines for future research in normative multi-agent systems.

  • 446. Chronoopoulos, Michail
    et al.
    De Reyck, Bert
    Siddiqui, Afzal
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap. University College London, UK.
    The value of capacity sizing under risk aversion and operational flexibility2013Ingår i: IEEE transactions on engineering management, ISSN 0018-9391, E-ISSN 1558-0040, Vol. 60, nr 2, s. 272-288Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Risk aversion typically erodes the value of an investment opportunity, often increasing the incentive to delay investment. Although this may be true when the decision maker has discretion only over the timing of investment, any additional discretion over the capacity of a project may lead to different results. In this paper, we extend the traditional real options approach by allowing for discretion over capacity while incorporating risk aversion and operational flexibility in the form of suspension and resumption options. In contrast to a project without scalable capacity, we find that increased risk aversion may actually facilitate investment because it decreases the optimal capacity of the project. Finally, we illustrate how the relative loss in the value of the investment opportunity due to an incorrect capacity choice may become less pronounced with increasing risk aversion and uncertainty.

  • 447. Chronopoulos, Michail
    et al.
    Bunn, Derek
    Siddiqui, Afzal
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap. University College London, UK.
    Optionality and Policymaking in Re-Transforming the British Power Market2014Ingår i: Economics of Energy & Environmental Policy, ISSN 2160-5882, E-ISSN 2160-5890, Vol. 3, nr 2, s. 79-100Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Conventional models to support policymaking for the energy sector have been largely based on deterministic or static settings that focus on planning welfare-maximising investment pathways. But, in a liberalised market, since investments are made by competitive, profit-maximising companies, the increased intervention of government policy in the trading arrangements creates uncertain responses to incentives. Industry may perceive policy risks to be high, and major companies may choose to act more cautiously than governments expect. This presents a modelling challenge, and we propose an extension to the use of real options in this context. We model several features of the low-carbon investment context, viz., irreversibility, delay, and competition, which impinge upon the radical policy imperatives for structural change in electricity markets to meet ambitious sustainability targets.

  • 448. Chronopoulos, Michail
    et al.
    De Reyck, Bert
    Siddiqui, Afzal
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap. University of London, England.
    Duopolistic competition under risk aversion and uncertainty2014Ingår i: European Journal of Operational Research, ISSN 0377-2217, E-ISSN 1872-6860, Vol. 236, nr 2, s. 643-656Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A monopolist typically defers entry into an industry as both price uncertainty and the level of risk aversion increase. By contrast, the presence of a rival typically hastens entry under risk neutrality. Here, we examine these two opposing effects in a duopoly setting. We demonstrate that the value of a firm and its entry decision behave differently with risk aversion and uncertainty depending on the type of competition. Interestingly, if the leader's role is defined endogenously, then higher uncertainty makes her relatively better off, whereas with the roles exogenously defined, the impact of uncertainty is ambiguous.

  • 449. Chronopoulos, Michail
    et al.
    De Reyck, Bert
    Siddiqui, Afzal
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Optimal investment under operational flexibility, risk aversion, and uncertainty2011Ingår i: European Journal of Operational Research, ISSN 0377-2217, E-ISSN 1872-6860, Vol. 213, nr 1, s. 221-237Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Traditional real options analysis addresses the problem of investment under uncertainty assuming a risk-neutral decision maker and complete markets. In reality, however, decision makers are often risk averse and markets are incomplete. We confirm that risk aversion lowers the probability of investment and demonstrate how this effect can be mitigated by incorporating operational flexibility in the form of embedded suspension and resumption options. Although such options facilitate investment, we find that the likelihood of investing is still lower compared to the risk-neutral case. Risk aversion also increases the likelihood that the project will be abandoned, although this effect is less pronounced. Finally, we illustrate the impact of risk aversion on the optimal suspension and resumption thresholds and the interaction among risk aversion, volatility, and optimal decision thresholds under complete operational flexibility.

  • 450. Chronopoulos, Michail
    et al.
    Siddiqui, Afzal
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap. University College London, UK.
    When is it better to wait for a new version? Optimal replacement of an emerging technology under uncertainty2015Ingår i: Annals of Operations Research, ISSN 0254-5330, E-ISSN 1572-9338, Vol. 235, nr 1, s. 177-201Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Firms that use an emerging technology often face uncertainty in both the arrival of new versions and the revenue that may be earned from their deployment. Via a sequential decision-making framework, we determine the value of the investment opportunity and the optimal replacement rule under three different strategies: compulsive, laggard, and leapfrog. In the first one, a firm invests sequentially in every version that becomes available, whereas in the second and third ones, it first waits for a new version to arrive and then either invests in the older or the newer version, respectively. We show that, under a compulsive strategy, technological uncertainty has a non-monotonic impact on the optimal investment decision. In fact, uncertainty regarding the availability of future versions may actually hasten investment. By comparing the relative values of the three strategies, we find that, under a low output price the compulsive strategy always dominates, whereas, at a high output price, the incentive to wait for a new version and adopt either a leapfrog or a laggard strategy increases as the rate of innovation increases. By contrast, high price uncertainty mitigates this effect, thereby increasing the relative attraction of a compulsive strategy.

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