Change search
Refine search result
1 - 19 of 19
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1. Boeva, V
    et al.
    Ekenberg, Love
    KTH, Superseded Departments, Computer and Systems Sciences, DSV.
    A transition logic for schemata conflicts2004In: Data & Knowledge Engineering, ISSN 0169-023X, E-ISSN 1872-6933, Vol. 51, no 3, p. 277-294Article in journal (Refereed)
    Abstract [en]

    Conflict detection and analysis are of high importance, e.g., when integrating conceptual schemata, such as UML-Specifications, or analysing goal-fulfilment of sets of autonomous agents. In general, models for this introduce unnecessarily complicated frameworks with several disadvantages regarding semantics as well as complexity. This paper demonstrates that an important set of static and dynamic conflicts between specifications can be diagnosed using ordinary first-order modal logic. Furthermore, we show how the framework can be extended for handling situations when there are convex sets of probability measures over a state-space. Thus, representing specifications as conceptual schemata and using standard Kripke models of modal logic, augmented with an interval-valued probability measure, we propose instrumental definitions and procedures for conflict detection.

  • 2.
    Brouwers, Lisa
    et al.
    KTH, Superseded Departments, Computer and Systems Sciences, DSV.
    Ekenberg, Love
    KTH, Superseded Departments, Computer and Systems Sciences, DSV.
    Hansson, Karin
    KTH, Superseded Departments, Computer and Systems Sciences, DSV.
    Danielson, Mats
    Multi-criteria decision-making of policy strategies with public-private re-insurance systems2004In: Risk, Decision, and Policy, ISSN 1357-5309, E-ISSN 1466-4534, Vol. 9, no 1, p. 23-45Article in journal (Refereed)
    Abstract [en]

    This article describes an integrated flood catastrophe model as well as some results of a case study made in the Upper Tisza region in north-eastern Hungary: the Palad-Csecsei basin. The background data was provided through the Hungarian Academy of Sciences and complemented by interviews with different stakeholders in the region. Based on these data, for which a large degree of uncertainty is prevailing, we demonstrate how an implementation of a simulation and decision analytical model can provide insights into the effects of imposing different policy options for a flood risk management program in the region. We focus herein primarily on general options for designing a public-private insurance and reinsurance system for Hungary. Obviously, this is a multi-criteria and multi-stakeholder problem and cannot be solved using standard approaches. It should, however, be emphasised that the main purpose of this article is not to provide any definite recommendations, but rather to explore a set of policy packages that could gain a consensus among the stakeholders.

  • 3.
    Danielson, Mats
    et al.
    KTH, School of Information and Communication Technology (ICT), Computer and Systems Sciences, DSV.
    Ekenberg, Love
    KTH, School of Information and Communication Technology (ICT), Computer and Systems Sciences, DSV.
    Computing upper and lower bounds in interval decision trees2007In: European Journal of Operational Research, ISSN 0377-2217, E-ISSN 1872-6860, Vol. 181, no 2, p. 808-816Article in journal (Refereed)
    Abstract [en]

    This article presents algorithms for computing optima in decision trees with imprecise probabilities and utilities. In tree models involving uncertainty expressed as intervals and/or relations, it is necessary for the evaluation to compute the upper and lower bounds of the expected values. Already in its simplest form, computing a maximum of expectancies leads to quadratic programming (QP) problems. Unfortunately, standard optimization methods based on QP (and BLP - bilinear programming) are too slow for the evaluation of decision trees in computer tools with interactive response times. Needless to say, the problems with computational complexity are even more emphasized in multi-linear programming (MLP) problems arising from multi-level decision trees. Since standard techniques are not particularly useful for these purposes, other, non-standard algorithms must be used. The algorithms presented here enable user interaction in decision tools and are equally applicable to all multi-linear programming problems sharing the same structure as a decision tree.

  • 4.
    Danielson, Mats
    et al.
    KTH, School of Information and Communication Technology (ICT), Computer and Systems Sciences, DSV.
    Ekenberg, Love
    KTH, School of Information and Communication Technology (ICT), Computer and Systems Sciences, DSV.
    Larsson, Aron
    Distribution of expected utility in decision trees2007In: International Journal of Approximate Reasoning, ISSN 0888-613X, E-ISSN 1873-4731, Vol. 46, no 2, p. 387-407Article in journal (Refereed)
    Abstract [en]

    Evaluation of decision trees in which imprecise information prevails is complicated. Especially when the tree has some depth, i.e. consists of more than one level, the effects of the choice of representation and evaluation procedures are significant. Second-order representation and evaluation may significantly increase a decision-maker's understanding of a decision situation when handling aggregations of imprecise representations, as is the case in decision trees or influence diagrams, while the use of only first-order results gives an incomplete picture. Furthermore, due to the effects on the distribution of belief over the intervals of expected utilities, the Gamma-maximin decision rule seems to be unnecessarily pessimistic as the belief in neighbourhoods of points near interval boundaries is usually lower than in neighbourhoods near the centre. Due to this, a generalized expected utility is proposed. The results in this paper apply also to approaches, which do not explicitly deal with second-order information, such as standard decision trees or probabilistic networks using only first-order concepts, for example upper and lower bounds. Furthermore, the results also apply to other, non-probabilistic weighted trees such as multi-criteria weight trees.

  • 5.
    Davies, Guy
    et al.
    KTH, School of Information and Communication Technology (ICT), Computer and Systems Sciences, DSV.
    Ekenberg, Love
    KTH, School of Information and Communication Technology (ICT), Computer and Systems Sciences, DSV.
    Some observations on elusion, enrichment and domination2008Conference paper (Refereed)
    Abstract [en]

    Conceptual schemata each representing some component of a system in the making, can be integrated in a variety of ways. Herein, we explore some fundamental notions of this. More particularly, we investigate some ways in which integration through correspondence assertions affects the interrelationship of two component schemata. One of the consequences of combining schemata is the appearance of events, for the united schema, that allow spurious transitions between models, transitions that would not have been possible in one of the original schemata. Much previous work has focussed on dominance with regard to preservation of information capacity as a primary integration criterion. However, even though it is desirable that the information capacity of a combined schema dominate one or both of its constituent schemata, we here discuss some aspects of why domination based on information capacity is insufficient for the integration to be semantically satisfactory.

  • 6.
    Ekenberg, Love
    KTH, School of Information and Communication Technology (ICT), Computer and Systems Sciences, DSV.
    A gentle introduction to system verification2005In: New trends in software methodologies, tools and techniques, Amsterdam: IOS Press, 2005, p. 173-193Conference paper (Refereed)
    Abstract [en]

    Verification is an important instrument in the analysis of systems. Roughly, this means that requirements and designs are analyzed formally to determine their relationships. Various candidates for formalizing system development and integration have been proposed. However, a major obstacle is that these introduce non-standard objects and formalisms, leading to severe confusion. This is because these models often are unnecessarily complicated with several disadvantages regarding semantics as well as complexity. While avoiding the mathematical details as far as possible, we present some basic verification ideas using a simple language Such as predicate logic and demonstrate how this can be used for defining and analyzing static and dynamic requirement fulfillment by designs as well as for detecting conflicts. The formalities can be found in the appendix.

  • 7.
    Ekenberg, Love
    et al.
    KTH, School of Information and Communication Technology (ICT), Computer and Systems Sciences, DSV.
    Andersson, Mikael
    Danielson, Mats
    Larsson, Aron
    Distributions over Expected Utilities in Decision Analysis2007Conference paper (Refereed)
    Abstract [en]

    It is often recognised that in real-life decision situations, classical utility theory puts too strong requirements on the decision-maker. Various interval approaches for decision making have therefore be. developed and these have been reasonably successful. However, a problem that sometimes appears in real-life situations is that the result of an evaluation still has an uncertainty about which alternative is to prefer. This is due to expected utility overlaps rendering discrimination more difficult;. In this article we discuss how adding second-order information may increase a decision-maker's understanding of a decision situation when handling aggregations of imprecise representations, as is the case in decision trees or influence diagrams.

  • 8.
    Ekenberg, Love
    et al.
    KTH, School of Information and Communication Technology (ICT), Computer and Systems Sciences, DSV. Mid Sweden University, Sweden .
    Danielson, M.
    Larsson, A.
    Second order effects in interval valued decision graph models2005In: Proceedings of the Eighteenth International Florida Artificial Intelligence Research Society Conference, FLAIRS 2005 - Recent Advances in Artifical Intelligence, 2005, p. 728-733Conference paper (Refereed)
    Abstract [en]

    Second-order calculations may significantly increase a decision maker's understanding of a decision situation when handling aggregations of imprecise representations, as is the case in decision trees or influence diagrams, while the use of only first-order results gives an incomplete picture. The results apply also to approaches which do not explicitly deal with second-order distributions, instead using only first-order concepts such as upper and lower bounds.

  • 9.
    Ekenberg, Love
    et al.
    KTH, Superseded Departments, Computer and Systems Sciences, DSV.
    Johannesson, Paul
    KTH, Superseded Departments, Computer and Systems Sciences, DSV.
    A framework for determining design correctness2004In: Knowledge-Based Systems, ISSN 0950-7051, E-ISSN 1872-7409, Vol. 17, no 07-8, p. 249-262Article in journal (Refereed)
    Abstract [en]

    Quality is one of the main concerns in today's systems and software development and use. One important instrument in verification is the use of formal methods, which means that requirements and designs are analyzed formally to determine their relationships. Furthermore, since professional software design is to an increasing extent a distributed process, the issue of integrating different systems to an entity is of great importance in modem system development and design. Various candidates for formalizing system development and integration have prevailed, but very often, particularly for dynamic conflict detection, these introduce non-standard objects and formalisms, leading to severe confusion, both regarding the semantics and the computability. In contrast to such, we introduce a framework for defining requirement fulfillment by designs, detecting conflicts of various kinds as well as integration of heterogeneous schemata. The framework introduced transcends ordinary logical consequence, as it takes into account static and dynamic aspects of design consistency and, in particular, the specific features of the state space of a specification. Another feature of the approach is that it provides a unifying framework for design conflict analysis and schema integration.

  • 10.
    Ekenberg, Love
    et al.
    KTH, School of Information and Communication Technology (ICT), Computer and Systems Sciences, DSV. Dept. of Information Technology and Media, Mid Sweden University, Sweden .
    Larsson, A.
    Danielson, M.
    Second-order risk constraints2008In: Proceedings of the 21th International Florida Artificial Intelligence Research Society Conference, FLAIRS-21, 2008, p. 637-642Conference paper (Refereed)
    Abstract [en]

    This paper discusses how numerically imprecise information can be modelled and how a risk evaluation process can be elaborated by integrating procedures for numerically imprecise probabilities and utilities. More recently, representations and methods for stating and analysing probabilities and values (utilities) with belief distributions over them (second order representations) have been suggested. In this paper, we are discussing some shortcomings in the use of the principle of maximising the expected utility and of utility theory in general, and offer remedies by the introduction of supplementary decision rules based on a concept of risk constraints taking advantage of second-order distributions.

  • 11.
    Hansson, Karin
    et al.
    KTH, School of Information and Communication Technology (ICT), Computer and Systems Sciences, DSV.
    Danielson, Mats
    KTH, School of Information and Communication Technology (ICT), Computer and Systems Sciences, DSV.
    Ekenberg, Love
    KTH, School of Information and Communication Technology (ICT), Computer and Systems Sciences, DSV.
    A framework for evaluation of flood management strategies2008In: Journal of Environmental Management, ISSN 0301-4797, E-ISSN 1095-8630, Vol. 86, no 3, p. 465-480Article in journal (Refereed)
    Abstract [en]

    The resulting impact of disasters on society depends on the affected country's economic strength prior to the disaster. The larger the disaster and the smaller the economy, the more significant is the impact. This is clearest seen in developing countries, where weak economics become even weaker afterwards. Deliberate strategies for the sharing of losses from hazardous events may aid a country or a community in efficiently using scarce prevention and mitigation resources, thus being better prepared for the effects of a disaster. Nevertheless, many governments lack an adequate institutional system for applying cost effective and reliable technologies for disaster prevention, early warnings, and mitigation. Modelling by event analyses and strategy models is one way of planning ahead, but these models have so far not been linked together. An approach to this problem was taken during a large study in Hungary, the Tisza case study, where a number of policy strategies for spreading of flood loss were formulated. In these strategies, a set of parameters of particular interest were extracted from interviews with stakeholders in the region. However, the study was focused on emerging economies, and, in particular, on insurance strategies. The scope is now extended to become a functional framework also for developing countries. In general, they have a higher degree of vulnerability. The paper takes northern Vietnam as an example of a developing region. We identify important parameters and discuss their importance for flood strategy formulations. Based on the policy strategies in the Tisza case, we extract data from the strategies and propose a framework for loss spread in developing and emerging economics. The parameter set can straightforwardly be included in a simulation and decision model for policy formulation and evaluation, taking multiple stakeholders into account.

  • 12. Larsson, A.
    et al.
    Ekenberg, Love
    KTH, School of Information and Communication Technology (ICT), Computer and Systems Sciences, DSV.
    Danielson, M.
    Non-uniform belief in expected utilities in interval decision analysis2005In: Proc. Int. Florida Artif. Intell. Res. Soc. Conf. Recent Adv. Artif. Intell., 2005, p. 740-745Conference paper (Refereed)
    Abstract [en]

    This paper demonstrates that second-order calculations add information about expected utilities when modeling imprecise information in decision models as intervals and employing the principle of maximizing the expected utility. Furthermore, due to the resulting warp in the distribution of belief over the intervals of expected utilities, the conservative Γ-maximin decision rule seems to be unnecessarily conservative and pessimistic as the belief in neighborhoods of points near interval boundaries is significantly lower than in neigh-borhoods near the centre. Due to this, a generalized expected utility is proposed.

  • 13. Larsson, A.
    et al.
    Johansson, J.
    Ekenberg, Love
    KTH, Superseded Departments, Numerical Analysis and Computer Science, NADA.
    Danielson, M.
    Multi-attribute decision tree evaluation in imprecise and uncertain domains2004In: Proc. Seventeenth Int. Fla. Artif. Intell. Res. Soc. Conf. FLAIRS, 2004, p. 850-855Conference paper (Refereed)
    Abstract [en]

    We present a decision tree evaluation method integrated with a common framework for analyzing multi-attribute decisions under risk, where information is numerically imprecise. The approach extends the use of additive and multiplicative utility functions for supporting evaluation of imprecise statements, relaxing requirements for precise estimates of decision parameters. Information is modeled in convex sets of utility and probability measures restricted by closed intervals. Evaluation is done relative to a set of rules, generalizing the concept of admissibility, computationally handled through optimization of aggregated utility functions. Pros and cons of two approaches, and tradeoffs in selecting a utility function, are discussed.

  • 14. Larsson, A.
    et al.
    Johansson, J.
    Ekenberg, Love
    KTH, School of Information and Communication Technology (ICT), Computer and Systems Sciences, DSV.
    Danielson, Mats
    KTH, School of Information and Communication Technology (ICT), Computer and Systems Sciences, DSV.
    Decision analysis with multiple objectives in a framework for evaluating imprecision2005In: International Journal of Uncertainty Fuzziness and Knowledge-Based Systems, ISSN 0218-4885, Vol. 13, no 5, p. 495-509Article in journal (Refereed)
    Abstract [en]

    We present a decision tree evaluation method for analyzing multi-attribute decisions under risk, where information is numerically imprecise. The approach extends the use of additive and multiplicative utility functions for supporting evaluation of imprecise statements, relaxing requirements for precise estimates of decision parameters. Information is modeled in convex sets of utility and probability measures restricted by closed intervals. Evaluation is done relative to a set of rules, generalizing the concept of admissibility, computationally handled through optimization of aggregated utility functions. Pros and cons of two approaches, and tradeoffs in selecting a utility function, are discussed.

  • 15. Sundgren, David
    et al.
    Danielson, Mats
    KTH, School of Information and Communication Technology (ICT), Computer and Systems Sciences, DSV.
    Ekenberg, Love
    KTH, School of Information and Communication Technology (ICT), Computer and Systems Sciences, DSV.
    Warp effects on calculating interval probabilities2009In: International Journal of Approximate Reasoning, ISSN 0888-613X, E-ISSN 1873-4731, Vol. 50, no 9, p. 1360-1368Article in journal (Refereed)
    Abstract [en]

    in real-life decision analysis, the probabilities and utilities of consequences are in general vague and imprecise. One way to model imprecise probabilities is to represent a probability with the interval between the lowest possible and the highest possible probability, respectively. However, there are disadvantages with this approach; one being that when an event has several possible outcomes, the distributions of belief in the different probabilities are heavily concentrated toward their centres of mass, meaning that much of the information of the original intervals are lost. Representing an imprecise probability with the distribution's centre of mass therefore in practice gives much the same result as using an interval, but a single number instead of an interval is computationally easier and avoids problems such as overlapping intervals. We demonstrate why second-order calculations add information when handling imprecise representations, as is the case of decision trees or probabilistic networks. We suggest a measure of belief density for such intervals. We also discuss properties applicable to general distributions. The results herein apply also to approaches which do not explicitly deal with second-order distributions, instead using only first-order concepts such as upper and lower bounds.

  • 16.
    Sundgren, David
    et al.
    University of Gävle.
    Danielsson, Mats
    Dept. of Computer and Systems Sciences, Stockholm University, KTH.
    Ekenberg, Love
    Dept. of Computer and Systems Sciences, Stockholm University, KTH.
    Some second order effects on interval based probabilities2006In: FLAIRS 2006 - Proceedings of the Nineteenth International Florida Artificial Intelligence Research Society Conference, 2006, p. 848-853Conference paper (Refereed)
    Abstract [en]

    In real-life decision analysis, the probabilities and values of consequences are in general vague and imprecise. One way to model imprecise probabilities is to represent a probability with the interval between the lowest possible and the highest possible probability, respectively. However, there are disadvantages with this approach, one being that when an event has several possible out-comes, the distributions of belief in the different probabilities are heavily concentrated to their centers of mass, meaning that much of the information of the original intervals are lost. Representing an imprecise probability with the distribution's center of mass therefore in practice gives much the same result as using an interval, but a single number instead of an interval is computationally easier and avoids problems such as overlapping intervals. Using this, we demonstrate why second-order calculations can add information when handling imprecise representations, as is the case of decision trees or probabilistic networks. We suggest a measure of belief density for such intervals. We also demonstrate important properties when operating on general distributions. The results herein apply also to approaches which do not explicitly deal with second-order distributions, instead using only first-order concepts such as upper and lower bounds

  • 17.
    Sundgren, David
    et al.
    Univ Gavle, Gavle, Sweden..
    Ekenberg, Love
    KTH.
    Danielson, Mats
    Univ Stockholm, S-10691 Stockholm, Sweden..
    Shifted Dirichlet Distributions as Second-Order Probability Distributions that Factors into Marginals2009In: ISIPTA '09: PROCEEDINGS OF THE SIXTH INTERNATIONAL SYMPOSIUM ON IMPRECISE PROBABILITY: THEORIES AND APPLICATIONS / [ed] Augustin, T Coolen, FPA Moral, S Troffaes, MCM, SOC IMPRECISE PROBABILITY THEORY & APPLICATIONS-SIPTA , 2009, p. 405-+Conference paper (Refereed)
    Abstract [en]

    In classic decision theory it is assumed that a decision-maker can assign precise numerical values corresponding to the true value of each consequence, as well as precise numerical probabilities for their occurrences. In attempting to address real-life problems, where uncertainty in the input data prevails, some kind of representation of imprecise information is important. Second-order distributions, probability distributions over probabilities, is one way to achieve such a representation. However, it is hard to intuitively understand statements in a multi-dimensional space and user statements must be provided more locally. But the information-theoretic interplay between joint and marginal distributions may give rise to unwanted effects on the global level. We consider this problem in a setting of second-order probability distributions and find a family of distributions that normalised over the probability simplex equals its own product of marginals. For such distributions, there is no flow of information between the joint distributions and the marginal distributions other than the trivial fact that the variables belong to the probability simplex.

  • 18.
    Sundgren, David
    et al.
    Dept. of Mathematics, Natural and Computer Sciences, University of G¨avle,.
    Ekenberg, Love
    KTH, School of Information and Communication Technology (ICT), Computer and Systems Sciences, DSV.
    Danielsson, Mats
    KTH, School of Information and Communication Technology (ICT), Computer and Systems Sciences, DSV.
    Some properties of aggregated distributions over expected values2008In: / [ed] Gelbukh A., Morales E.F., Berlin: Springer Verlag , 2008, p. 699-709Conference paper (Refereed)
    Abstract [en]

    Software agents and humans alike face severe difficulties in making decisions in uncertain contexts. One approach is to formalise the decision situation by means of decision theory, i.e. probabilities and utilities leading to the principle of maximising the expected utility. Expected utility is here considered as a stochastic variable; under the assumption that all utility values are equally likely; and that each vector of probability values is equally likely, the probability distribution of expected utility is calculated for two, three, and four possible outcomes. The effect of these probability distributions concentrating around the middle value is explored and its significance for making decisions.

  • 19. Sutinen, M.
    et al.
    Danielson, M.
    Ekenberg, Love
    KTH, School of Information and Communication Technology (ICT), Computer and Systems Sciences, DSV. Stockholm University, Sweden.
    Larsson, A.
    Web-based analytical decision support system2010In: Proceedings of the 2010 10th International Conference on Intelligent Systems Design and Applications, ISDA'10, 2010, p. 575-579Conference paper (Refereed)
    Abstract [en]

    This paper presents a web-application supporting structured decision modelling and analysis. The application allows for decision modelling with respect to different preferences and views, allowing for numerically imprecise and vague background probabilities, values, and criteria weights, which further can be adjusted in an interactive fashion when considering calculated decision outcomes. The web-application is based on a decision tool that has been used in a large number of different domains over the last 15 years, ranging from investment decision analysis for companies to public decision support for local governments.

1 - 19 of 19
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf