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Search Results: 1 - 10 of 39 matches for " Audun Josang "
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The Cumulative Rule for Belief Fusion
Audun Josang
Computer Science , 2006,
Abstract: The problem of combining beliefs in the Dempster-Shafer belief theory has attracted considerable attention over the last two decades. The classical Dempster's Rule has often been criticised, and many alternative rules for belief combination have been proposed in the literature. The consensus operator for combining beliefs has nice properties and produces more intuitive results than Dempster's rule, but has the limitation that it can only be applied to belief distribution functions on binary state spaces. In this paper we present a generalisation of the consensus operator that can be applied to Dirichlet belief functions on state spaces of arbitrary size. This rule, called the cumulative rule of belief combination, can be derived from classical statistical theory, and corresponds well with human intuition.
Belief Calculus
Audun Josang
Computer Science , 2006,
Abstract: In Dempster-Shafer belief theory, general beliefs are expressed as belief mass distribution functions over frames of discernment. In Subjective Logic beliefs are expressed as belief mass distribution functions over binary frames of discernment. Belief representations in Subjective Logic, which are called opinions, also contain a base rate parameter which express the a priori belief in the absence of evidence. Philosophically, beliefs are quantitative representations of evidence as perceived by humans or by other intelligent agents. The basic operators of classical probability calculus, such as addition and multiplication, can be applied to opinions, thereby making belief calculus practical. Through the equivalence between opinions and Beta probability density functions, this also provides a calculus for Beta probability density functions. This article explains the basic elements of belief calculus.
Cumulative and Averaging Fission of Beliefs
Audun Josang
Computer Science , 2007,
Abstract: Belief fusion is the principle of combining separate beliefs or bodies of evidence originating from different sources. Depending on the situation to be modelled, different belief fusion methods can be applied. Cumulative and averaging belief fusion is defined for fusing opinions in subjective logic, and for fusing belief functions in general. The principle of fission is the opposite of fusion, namely to eliminate the contribution of a specific belief from an already fused belief, with the purpose of deriving the remaining belief. This paper describes fission of cumulative belief as well as fission of averaging belief in subjective logic. These operators can for example be applied to belief revision in Bayesian belief networks, where the belief contribution of a given evidence source can be determined as a function of a given fused belief and its other contributing beliefs.
Analysing Trust Transitivity and The Effects of Unknown Dependence
Touhid Bhuiyan,Audun Josang
International Journal of Engineering Business Management , 2010,
Abstract: Trust can be used to improve online automated recommendation within a given domain. Trust transitivity is used to make it successful. But trust transitivity has different interpretations. Trust and trust transitivity; both are the human mental phenomenon and for this reason, there is no such thing as objective transitivity. Trust transitivity and trust fusion both are important elements in computational trust. This paper analyses the parameter dependence problem in trust transitivity and proposes some definitions considering the effects of base rate. In addition, it also proposes belief functions based on subjective logic to analyse trust transitivity of three specified cases with sensitive and insensitive based rate. Then it presents a quantitative analysis of the effects of unknown dependence problem in an interconnected network environment; such Internet.
N, P, and K Budgets and Changes in Selected Topsoil Nutrients over 10 Years in a Long-Term Experiment with Conventional and Organic Crop Rotations
Audun Korsaeth
Applied and Environmental Soil Science , 2012, DOI: 10.1155/2012/539582
Abstract: This study presents soil system budgets of N, P and K in six contrasting cropping systems during 10 years of a long-term experiment in southeast Norway. The experiment included systems with arable cash-cropping and with mixed arable-dairy cropping (cash- and fodder crops), with organic and conventional management represented in both groups. All major nutrient inputs and outputs were measured or estimated. State of the art conventional cash-cropping appeared to be balanced in terms of N, whereas conventional mixed cropping had an N surplus. By contrast, less up to date conventional arable cash-cropping and all the organic systems showed indications of soil organic N depletion (negative N budgets). All the organic systems showed that mining of the soil P and K content occurs, whereas the conventional systems all had P and K surpluses. The results corresponded well with measured differences between systems in terms of ignition loss, P-AL, K-AL and K-HNO3 measured in 2009. This study shows that a fertile soil may be exposed to substantial mining of N, P and K over many years before it is detectable by traditional analyses, and that field nutrient budgeting is a feasible, but data-demanding, approach to detect such misbalances at an early stage. 1. Introduction In 1989, a large cropping system experiment, facilitated for measurements of runoff and leaching, was established at Apelsvoll in southeast Norway. Over the years, this experiment has provided data for many studies covering a range of different topics, including yields and yield quality (e.g., [1]), nutrient leaching and runoff losses (e.g., [2]), economic aspects (e.g., [3]), soil microbiology (e.g., [4]), soil physical and chemical properties (e.g., [5]), and the relation between food production and N losses [6]. Some major adjustments of the experimental design were made in 2000 [6]. In this overview, a synthesis of the results obtained after these changes are given for the major nutrient flows of N, P, and K, with focus on changes in topsoil nutrient pools, as affected by misbalances between nutrient inputs and outputs at field level. Numerous long-term experiments have shown that crop rotation and management affect soil fertility (e.g., [7–13]). However, considerable time is needed before identifiable changes in soil fertility emerge [14]. Nutrient budgets have been used widely in a range of farming systems to assess long-term sustainability (e.g., [15]), thus, supplementing soil measurements. In a discussion of uncertainties in nutrient budgets, Oenema et al. [16] distinguished between farm gate
Actividad opsonofagocítica contra meningococos del grupo B: ?Un correlato de protección adicional contra la enfermedad meningococica?
Aase,Audun;
Vaccimonitor , 2009,
Abstract: opsonophagocytic activity and serum bactericidal activity against group b meningococci were compared in sera from three vaccine groups given two different outer membrane vesicles vaccines separately or in combination. opsonophagocytic activity defined more responders and revealed more cross-reactivity against heterologous strains than observed with serum bactericidal activity, and it showed the highest correlation with igg-binding to live meningococci. determination of opsonophagocytic activity may therefore be a valuable laboratory supplement to serum bactericidal activity for monitoring protection against group b meningococcal disease.
A Mathematical Model for Dynamic Analysis of a Flexible Marine Riser Connected to a Floating Vessel
Audun Otteren
Modeling, Identification and Control , 1982, DOI: 10.4173/mic.1982.4.1
Abstract: A mathematical model for simulation of a flexible marine riser connected to a floating vessel is presented. The model is used for dynamic analysis of marine operations which include a riser and a floating vessel. The riser can be freely hanging from the vessel or fixed at the bottom. The vessel can be freely floating, moored by anchors or dynamically positioned. The performance of the riser model is evaluated by a comparison with results from a simulation study published by the American Petroleum Institute. Finally, a complete three dimensional, irregular sea-state analysis is presented to illustrate some of the capabilities of the simulation concept.
Opsonophagocytic activity against group b meningococci: An additional laboratory correlate of protection against meningococcal disease?
Audun Aase
Vaccimonitor , 2009,
Abstract: Opsonophagocytic activity and serum bactericidal activity against group B meningococci were compared in sera from three vaccine groups given two different outer membrane vesicles vaccines separately or in combination.Opsonophagocytic activity defined more responders and revealed more cross-reactivity against heterologous strains than observed with serum bactericidal activity, and it showed the highest correlation with IgG-binding to live meningococci. Determination of opsonophagocytic activity may therefore be a valuable laboratory supplement to serum bactericidal activity for monitoring protection against group B meningococcal disease.
Collective rights in a modernizing North - on institutionalizing Sámi and local rights to land and water in northern Norway
Audun Sandberg
International Journal of the Commons , 2008,
Abstract: The struggle by indigenous groups to have their rights acknowledged does not only take place through the action arenas of national political and constitutional processes, but also through active work through international bodies. Thus indigenous rights will often become arguments for institutional and constitutional changes in the modern world. The way such changes take place is nowadays more often through the incorporation of various forms of treaties and international charters into national legislation rather than direct negotiations between sovereign states and indigenous ‘tribes’, ‘clans’ or ethnic minority groups. However, when it comes to acknowledging the rights of ownership and possession of the peoples concerned over the lands which they traditionally occupy, these seem to be among the most difficult constitutional processes modern states can undertake. Thus they not only take much longer time than the granting of civil and political rights, but they also involve complex analytical exercises in order to understand the processes connected to the settling of indigenous land claims. This article analyses one such process in a nested and multi-tier system with parallel initiatives for institutional change.
State Space Realization of Model Predictive Controllers Without Active Constraints
Sigurd Skogestad,Audun Faanes
Modeling, Identification and Control , 2003, DOI: 10.4173/mic.2003.4.4
Abstract: To enable the use of traditional tools for analysis of multivariable controllers such as model predictive control (MPC), we develop a state space formulation for the resulting controller for MPC without constraints or assuming that the constraints are not active. Such a derivation was not found in the literature. The formulation includes a state estimator. The MPC algorithm used is a receding horizon controller with infinite horizon based on a state space process model. When no constraints are active, we obtain a state feedback controller, which is modified to achieve either output tracking, or a combination of input and output tracking. When the states are not available, they need to be estimated from the measurements. It is often recommended to achieve integral action in a MPC by estimating input disturbances and include their effect in the model. We show that to obtain offset free steady state the number of estimated disturbances must equal the number of measurements. The estimator is included in the controller equation, and we obtain a formulation of the overall controller with the set-points and measurements as inputs, and the manipulated variables as outputs. One application of the state space formulation is in combination with the process model to obtain a closed loop model. This can for example be used to check the steady-state solution and see whether integral action is obtained or not.
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