| 1. |
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| 2. |
- Victor, Trent, 1968, et al.
(author)
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Automation Expectation Mismatch: Incorrect Prediction Despite Eyes on Threat and Hands on Wheel
- 2018
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In: Human Factors. - : SAGE Publications. - 1547-8181 .- 0018-7208. ; 60:8, s. 1095-1116
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Journal article (peer-reviewed)abstract
- Objective: The aim of this study was to understand how to secure driver supervision engagement and conflict intervention performance while using highly reliable (but not perfect) automation. Background: Securing driver engagement—by mitigating irony of automation (i.e., the better the automation, the less attention drivers will pay to traffic and the system, and the less capable they will be to resume control) and by communicating system limitations to avoid mental model misconceptions—is a major challenge in the human factors literature. Method: One hundred six drivers participated in three test-track experiments in which we studied driver intervention response to conflicts after driving highly reliable but supervised automation. After 30 min, a conflict occurred wherein the lead vehicle cut out of lane to reveal a conflict object in the form of either a stationary car or a garbage bag. Results: Supervision reminders effectively maintained drivers’ eyes on path and hands on wheel. However, neither these reminders nor explicit instructions on system limitations and supervision responsibilities prevented 28% (21/76) of drivers from crashing with their eyes on the conflict object (car or bag). Conclusion: The results uncover the important role of expectation mismatches, showing that a key component of driver engagement is cognitive (understanding the need for action), rather than purely visual (looking at the threat), or having hands on wheel. Application: Automation needs to be designed either so that it does not rely on the driver or so that the driver unmistakably understands that it is an assistance system that needs an active driver to lead and share control.
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| 3. |
- Alpizar, Francisco, et al.
(author)
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Anonymity, Reciprocity, and Conformity: Evidence from Voluntary Contributions to a National Park in Costa Rica
- 2007
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Reports (other academic/artistic)abstract
- We investigate the role of anonymity, reciprocity, and conformity for voluntary contributions, based on a natural field experiment conducted at a national park in Costa Rica. Contributions made in public in front of the solicitor are 25% higher than contributions made in private. Giving subjects a small gift before requesting a contribution increases the likelihood of a positive contribution. At the same time, the conditional contribution decreases. The total effect of giving a gift is positive but small, and taking the cost of the gift into account, it is far from profitable. When the subjects are told that the typical contribution of others is $2 (a small contribution), the probability of a contribution increases and the conditional contribution decreases, compared with providing no reference information. Providing a high reference level ($10) increases the conditional contributions. Overall, the total effects have the expected signs, although the magnitudes are smaller than what one might have expected based on existing evidence from laboratory experiments.
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| 4. |
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| 5. |
- Alpizar, Francisco, 1974, et al.
(author)
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Does context matter more for hypothetical than for actual contributions? Evidence from a natural field experiment
- 2007
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Reports (other academic/artistic)abstract
- We investigate the importance of the social context for people’s voluntary contributions to a national park in Costa Rica, using a natural field experiment. Some subjects make actual contributions while others state their hypothetical contribution. Both the degree of anonymity and provided information about the contributions of others influence subject contributions in the hypothesized direction. We do find a substantial hypothetical bias with regard to the amount contributed. However, the influence of the social contexts is about the same when the subjects make actual monetary contributions as when they state their hypothetical contributions. Our results have important implications for validity testing of stated preference methods: a comparison between hypothetical and actual behavior should be done for a given social context.
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| 6. |
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| 7. |
- Alpizar, Francisco, 1974, et al.
(author)
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How Much Do We Care About Absolute versus Relative Income and Consumption?
- 2005
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In: Journal of Economic Behavior and Organization. - : Elsevier BV. - 0167-2681. ; 56, s. 405-421
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Journal article (peer-reviewed)abstract
- We find, using survey-experimental methods, that most individuals are concerned with both relative income and relative consumption of particular goods. The degree of concern varies in the expected direction depending on the properties of the good. However, contrary to what has been suggested in the previous literature, we find that relative consumption is also important for vacation and insurance, which are typically seen as non-positional goods. Further, absolute consumption is also found to be important for cars and housing, which are widely regarded as highly positional. © 2004 Published by Elsevier B.V.
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| 8. |
- Alpizar, Francisco, 1974, et al.
(author)
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How Much Do We Care About Absolute Versus Relative Income and Consumption?
- 2001
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Reports (other academic/artistic)abstract
- We find, using survey-experimental methods, that most individuals are concerned with both relative income and relative consumption of particular goods. The degree of concern varies in the expected direction depending on the properties of the good. However, contrary to what has been suggested in the previous literature, we find that relative consumption is also important for vacation and insurance, which are typically seen as non-positional goods. Further, absolute consumption is also found to be important for cars and housing, which are widely regarded as highly positional. Implications for Pareto-efficient taxation are illustrated using the results from the experiment.
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| 9. |
- Carlsson, Fredrik, 1968, et al.
(author)
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Are people inequality averse or just risk averse?
- 2001
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Reports (other academic/artistic)abstract
- Individuals' preferences for risk and inequality are measured through experimental choices between hypothetical societies and lotteries. The median relative risk aversion, which is often seen to reflect social inequality aversion, is between 2 and 3. We also estimate the individual inequality aversion, reflecting individuals' willingness to pay for living in a more equal society.Left-wing voters and women are both more risk- and inequality averse than others. The model allows for non-monotonic SWFs, implying that welfare may decrease with an individual's income at high income levels. This is illustrated in simulations based on the empirical results.
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| 10. |
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| 11. |
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| 12. |
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| 13. |
- Carlsson, Fredrik, 1968, et al.
(author)
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Choosing from Behind a Veil of Ignorance in India
- 2002
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Reports (other academic/artistic)abstract
- Social inequality aversion is measured through a veil-of-ignorance experiment with Indian students. The median relative risk aversion is found to be quite high, about 3, and independent caste.
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| 14. |
- Carlsson, Fredrik, 1968, et al.
(author)
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Do You Enjoy Having More Than Others? Survey Evidence of Positional Goods
- 2003
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Reports (other academic/artistic)abstract
- Although conventional economic theory proposes that only the absolute levels of income and consumption matter for people´s utility, there is much evidence that relative concerns are often important. This paper uses a survey-experimental method to measure people´s perceptions of the degree to which such concerns matter, i.e. the degree of positionality. Based on a representative sample in Sweden, income and cars are found to be highly positional, on average. This is in contrast to leisure and car safety, which may even be completely non-positional.
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| 15. |
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| 16. |
- Carlsson, Fredrik, 1968, et al.
(author)
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Funding a New Bridge in Rural Vietnam: A field experiment on conditional cooperation and default contributions
- 2011
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Reports (other academic/artistic)abstract
- The ability to provide public goods is essential for economic and social development, yet there is very limited empirical evidence regarding contributions to a real local public good in developing countries. This paper analyzes a field experiment where 200 households in rural Vietnam could make real contributions to an archetypical public good, a bridge. In particular, we study the role of two kinds of social influence: i) conditional cooperation, i.e., that people may be more willing to cooperate if others do, and ii) the effects of the default alternative, i.e., that people are influenced by the default alternative presented to them in the choice situation. We find significant and substantial effects of both kinds of influence. For example, by either giving the subjects the additional information that one of the most common contributions by others is 100,000 dong (a relatively low contribution) or introducing a zero-contribution default alternative, the average contribution decreases by about 20% compared to the baseline case.
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| 17. |
- Carlsson, Fredrik, 1968, et al.
(author)
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Funding a new bridge in rural Vietnam:a field experiment on social influence and default contributions
- 2015
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In: Oxford Economic Papers. - : Oxford University Press (OUP). - 0030-7653 .- 1464-3812. ; 67:4, s. 987-1014
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Journal article (peer-reviewed)abstract
- Public goods provision is essential for economic development. Yet there is limited evidence regarding contributions to local public goods in developing countries. This article analyses a field experiment where all 200 households in a village in rural Vietnam make real contributions to a public good that is very important for them in daily life—a bridge. We study the role of social influence (that people may be more willing to co-operate if others do) and the effects of the default alternative in the choice situation. We find significant and substantial (in the order of magnitude of 15–25%) effects of both social influence and defaults but only when providing low reference or default contributions.
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| 18. |
- Carlsson, Fredrik, 1968, et al.
(author)
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How Much Liberty Should We Have? Citizens versus Experts on Regulating Externalities and Internalities
- 2024
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Other publication (other academic/artistic)abstract
- Based on a tailor-made survey, we find that experts – academics and civil servants – are much more willing than citizens in Sweden to accept liberty-reducing regulations. Moreover, both citizens and experts are more supportive of regulating negative internalities (in terms of health) than negative externalities (in terms of climate change). While less liberty-reducing policy instruments receive more support, around 20 percent of citizens and experts support very intrusive measures such as non-transferable individual quotas for air travel and unhealthy foods. Both experts and citizens prefer encouraging to discouraging information provision, while experts are more positive than citizens to tax instruments
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| 19. |
- Carlsson, Fredrik, 1968, et al.
(author)
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Is Transport Safety More Valuable in the Air?
- 2002
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Reports (other academic/artistic)abstract
- Using a contingent valuation survey, people?s willingness to pay for a given risk reduction is found to be much larger when traveling by air compared to by taxi. Follow-up questions revealed that an important reason for this discrepancy is that many experience a higher mental suffering from flying, and that they are willing to pay to reduce this suffering. It was also consistently found that people are willing to pay more for a certain risk reduction if the original price was higher. Policy implications are discussed.
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| 20. |
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| 21. |
- Carlsson, Fredrik, 1968, et al.
(author)
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Keeping Up with the Vaishyas: Caste and Relative Standing
- 2005
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Reports (other academic/artistic)abstract
- We investigate the importance of relative income within the Indian Caste system, using a choice experiment. We find that slightly more than half of the marginal utility of income comes from some kind of relative income effects, on average, which is comparable to the results from previous studies in other countries. Belonging to a low caste and having a low family income are associated with higher concern for relative income. Moreover, an increase in the mean income of the caste to which the individual belongs, everything else held constant, reduces utility for the individual. Thus, the negative welfare effect of reduced relative income compared to the average own caste income dominates the positive welfare effect of increased relative income of the own caste relative to other castes.
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| 22. |
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| 23. |
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| 24. |
- Carlsson, Fredrik, 1968, et al.
(author)
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Nudging as an Environmental Policy Instrument
- 2019
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Reports (other academic/artistic)abstract
- We discuss the use of green nudges – nudges intended to reduce negative externalities – as an environmental policy instrument. A review of empirical studies reveals that green nudges can have a sizeable impact on behavior and the environment, but that the effects are context dependent. In the policy discussion, drawing on both the empirical overview and basic welfare-economic models, it is emphasized that while green nudges seem to have a large potential, they offer no panacea for solving environmental problems. Instead, they should be seen as a policy instrument among others in the regulator’s toolbox. In particular, we discuss the potential role of nudging when environmental externalities can be dealt with using optimal Pigovian taxes, and when they cannot. Nudging has a greater potential when such taxes are not available or feasible.
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| 25. |
- Carlsson, Fredrik, 1968, et al.
(author)
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Optimal Prosocial Nudging
- 2019
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Reports (other academic/artistic)abstract
- While nudges are still mostly associated with affecting individual choices for their own long-run interest, i.e. dealing with internalities, they are increasingly used in order to reduce externalities, such as environmental consequences. While we are gaining increasing insights into when and how nudges work, much less attention has been given to the normative aspects of nudging as a policy instrument to deal with externalities. We investigate optimal prosocial nudging under a number of different settings in a world where a conventional Pigovian tax can be used to a varying extent. We find that nudges typically only play a limited role when optimal taxes can be implemented. What we denote encouraging moral nudges, i.e. nudges where people’s choices are affected by strengthening consumers’ moral norms for doing the right thing, are more likely to play a role even when the tax is optimal compared to purely cognitive nudges. In addition, if a nudge better can target the right consumers, then it might also be optimal to use even when an optimal tax can be implemented. We also present decision rules for the optimal size of a nudge when an optimal tax cannot be implemented.
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| 26. |
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| 27. |
- Carlsson, Fredrik, 1968, et al.
(author)
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Should We Trust Hypothetical Referenda? Test and Identification Problems
- 2006
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Reports (other academic/artistic)abstract
- In a paper published in the Journal of Political Economy, Cummings et al. experimentally compare hypothetical and real-money referenda. They reject the incentive compatibility hypothesis of hypothetical referenda. However, in a comment, Haab et al. claim that the hypothesis cannot be rejected if one corrects for heteroskedasticity. In this note we show that the methodology used by Haab et al. is flawed, and their conclusions unwarranted. Our results rather support the original conclusion that hypothetical referenda appears not to resemble real referenda (unless one has reasons to believe that the true variance is much larger in the hypothetical case). This paper outlines design and identification difficulties arising when statistically comparing real and hypothetical referenda.
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| 28. |
- Carlsson, Fredrik, 1968, et al.
(author)
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Social preferences are stable over long periods of time
- 2012
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Reports (other academic/artistic)abstract
- We measure people’s prosocial behavior, in terms of voluntary money and labor time contributions to an archetypical public good, a bridge, and in terms of voluntary money contributions in a public good game, using the same non-student sample in rural Vietnam at four different points in time from 2005 to 2011. Two of the experiments are natural experiment, one is a field experiment and one is a public good experiment. Since the experiments were conducted far apart in time, the potentially confounding effects of moral licensing and moral cleansing are presumably small, if existing at all. Despite large contextual variations, we find a strong positive and statistically significant correlation between voluntary contributions in these experiments, whether correcting for other covariates or not. This suggests that pro-social preferences are fairly stable over long periods of time and contexts.
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| 29. |
- Carlsson, Fredrik, 1968, et al.
(author)
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Social preferences are stable over long periods of time
- 2014
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In: Journal of Public Economics. - : Elsevier BV. - 0047-2727. ; 117, s. 104-114
-
Journal article (peer-reviewed)abstract
- We measure people's pro-social behavior, in terms of voluntary money and labor contributions to an archetypical public good, a bridge, and in terms of voluntary money contributions in a public good game, using the same non-student sample in rural Vietnam at four different points in time from 2005 to 2011. Two of the observed events are actual voluntary contributions (one in terms of money and one in terms of labor), one is from a natural field experiment, and one is from an artefactual field experiment. Despite large contextual variations, we find a strong positive and statistically significant correlation between voluntary contributions, whether correcting for other covariates or not. This suggests that pro-social preferences are fairly stable over long periods of time and contexts.
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| 30. |
- Carlsson, Fredrik, 1968, et al.
(author)
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The Costs and Benefits of Electric Vehicles: A 2010 perspective
- 2003
-
In: Journal of Transport Economics and Policy. ; 37, s. 1-28
-
Journal article (peer-reviewed)abstract
- This paper undertakes a social cost-benefit analysis regarding an increase in the number of electric vehicles in the Swedish transport sector by year 2010. Battery cars are generally found to be socially unprofitable, even though their private life-cycle costs and external costs are lower than those of gasoline cars. One important reason for this is that electric vehicles are heavily â??subsidisedâ?? by having, in comparison with taxes on fossil fuel, a very low electricity tax. â??Hybridâ?? cars are more likely to be socially profitable, especially for city-based delivery trucks, which may be both privately and socially profitable without subsidies.
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| 31. |
- Carlsson, Fredrik, 1968, et al.
(author)
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The Use of Green Nudges as an Environmental Policy Instrument
- 2021
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In: Review of Environmental Economics and Policy. - : University of Chicago Press. - 1750-6816 .- 1750-6824. ; 15:2, s. 216-237
-
Journal article (peer-reviewed)abstract
- This article discusses the use of green nudges—behavioral interventions aimed at reducing negative externalities—as an environmental policy instrument. We present a new framework for classifying nudges according to how they affect behavior. Pure nudges change the choice environment to guide behavior unobtrusively. Moral nudges trigger a psychological reaction to encourage behavior change. Our review of empirical studies reveals that green nudges, pure or moral, can have a significant impact on behavior and the environment but that the effects are highly context dependent. On the basis of both our review and basic welfare economics models, we discuss key factors for policy makers to consider when choosing between implementing a green nudge and implementing conventional policy instruments.
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| 32. |
- Carlsson, Fredrik, 1968, et al.
(author)
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Voting Motives, Group Identity, and Social Norms
- 2009
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Reports (other academic/artistic)abstract
- The conventional rational voter model has problems explaining why people vote, since the costs typically exceed the expected benefits. This paper presents Swedish survey evidence suggesting that people vote based on a combination of instrumental and expressive motives, and that people are strongly influenced by a social norm saying that it is an obligation to vote. Women and older individuals are more affected by this norm than others. The more rightwing a person is, the less unethical he/she will perceive selfish voting to be. Moreover, individuals believe that they themselves vote less selfishly than others and that people with similar political views as themselves vote less selfishly than people with the opposite political views, which is consistent with social identity theory.
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| 33. |
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| 34. |
- Daruvala, Dinky, 1962, et al.
(author)
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Measuring hypothetical grandparents preferences for quality and relative standings
- 2001
-
Reports (other academic/artistic)abstract
- Individuals' aversion to risk and inequality, and their concern for relative standing, are measured through experimental choices between hypothetical societies. It is found that on average individuals are both fairly inequality-averse and have a strong concern for relative income. The results are used to illustrate welfare consequences based on a utilitarian SWF and a modified CRRA utility function. It is shown that the social marginal utility of income may then become negative, even at income levels that are far from extreme.
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| 35. |
- Eliasson, Alf, 1959, et al.
(author)
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A retrospective analysis of early and delayed loading of full-arch mandibular prostheses using three different implant systems: clinical results with up to 5 years of loading.
- 2009
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In: Clinical implant dentistry and related research. - : Wiley. - 1708-8208 .- 1523-0899. ; 11:2, s. 134-48
-
Journal article (peer-reviewed)abstract
- BACKGROUND: Early loading of implant-supported prostheses in the edentulous mandible is widely accepted, but do the clinical results replicate those of delayed loading? PURPOSE: The aim of this study was to evaluate clinical outcome and patient satisfaction with early or delayed loading in patients treated with fixed prostheses, using three different implant systems. MATERIALS AND METHODS: One hundred and nine consecutively treated patients received 490 implants supporting fixed prostheses; 82 patients with Brånemark System implants (Nobel Biocare AB, Göteborg, Sweden), 16 with Astra Tech implants (Astra Tech AB Dental Implant system, Mölndal, Sweden), and 11 with ITI MonoType implants (ITI Dental Implant System, Institute Straumann AG, Waldenburg, Switzerland). Prostheses were placed within 2 to 3 weeks in 55 patients; 54 patients underwent a two-stage procedure. Data were collected from patient records and radiographs; 83 patients attended a clinical examination and received a questionnaire. RESULTS: All patients had fixed prostheses at follow-up with a mean observation time of 3.5 years. Cumulative survival rates (CSRs) were 92.5% of prostheses and 94.4% of implants for early loading, and 98.0 and 97.9% for delayed loading. The mean radiographic bone loss after the first year was small, and at 5 years less than 0.2 mm for both groups. With early loading, significantly more prostheses (p < .05) needed adjustment or replacement. CONCLUSION: Statistically significantly more prostheses needed adjustment or replacement in the early group. The present study suggested lower CSRs for prostheses and implants in the early loading group after 5 years; the difference was not statistically significant. Larger study samples are needed to verify statistically small differences between treatment techniques.
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| 36. |
- Fritze, Stefan, et al.
(author)
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Elemental distribution and fracture properties of magnetron sputtered carbon supersaturated tungsten films
- 2024
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In: Surface & Coatings Technology. - : Elsevier BV. - 0257-8972 .- 1879-3347. ; 477
-
Journal article (peer-reviewed)abstract
- The combination of strength and toughness is a major driving force for alloy design of protective coatings, and nanocrystalline tungsten (W)-alloys have shown to be promising candidates for combining strength and toughness. Here we investigate the elemental distribution and the fracture toughness of carbon (C) alloyed W thin films prepared by non-reactive magnetron sputtering. W:C films with up to ~4 at.% C crystallize in a body-centered-cubic structure with a strong 〈hh0〉texture, and no additional carbide phases are observed in the diffraction pattern. Atom probe tomography and X-ray photoelectron spectroscopy confirmed the formation of such a supersaturated solid solution. The pure W film has a hardness ~13 GPa and the W:C films exhibit a peak hardness of ~24 GPa. In-situ micromechanical cantilever bending tests show that the fracture toughness decreases from ~4.5 MPa·m1/2 for the W film to ~3.1 MPa·m1/2 for W:C films. The results show that C can significantly enhance the hardness of W thin films while retaining a high fracture toughness.
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| 37. |
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| 38. |
- Hessulf, Fredrik, 1986, et al.
(author)
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Campylobacter jejuni-associated perimyocarditis: two case reports and review of the literature
- 2016
-
In: Bmc Infectious Diseases. - : Springer Science and Business Media LLC. - 1471-2334. ; 16
-
Journal article (peer-reviewed)abstract
- Background: Campylobacter spp. are among the most common bacterial causes of gastroenteritis world-wide and mostly follow a benign course. We report two cases of Campylobacter jejuni-associated perimyocarditis, the first two simultaneous cases published to date and the third and fourth cases over all in Sweden, and a review of the literature. Case presentation: A previously healthy 24-yo male (A) presented at the Emergency Department(ED) with recent onset of chest pain and a 3-day history of abdominal pain, fever and diarrhoea. The symptoms began within a few hours of returning from a tourist visit to a central European capital. Vital signs were stable, the Electrocardiogram(ECG) showed generalized ST-elevation, laboratory testing showed increased levels of C-reactive protein(CRP) and high-sensitive Troponin T(hsTnT). Transthoracic echocardiogram (TTE) was normal, stool cultures were positive for C Jejuni and blood cultures were negative. Two days after patient A was admitted to the ED his travel companion (B), also a previously healthy male (23-yo), presented at the same ED with almost identical symptoms: chest pain precipitated by a few days of abdominal pain, fever and diarrhoea. Patient B declared that he and patient A had ingested chicken prior to returning from their tourist trip. Laboratory tests showed elevated CRP and hsTnT but the ECG and TTE were normal. In both cases, the diagnosis of C jejuni-associated perimyocarditis was set based on the typical presentation and positive stool cultures with identical strains. Both patients were given antibiotics, rapidly improved and were fully recovered at 6-week follow up. Conclusion: Perimyocarditis is a rare complication of C jejuni infections but should not be overlooked considering the risk of heart failure. With treatment, the prognosis of full recovery is good but several questions remain to be answered regarding the pathophysiology and the male preponderance of the condition.
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| 39. |
- Johansson, Björn G., 1968-
(author)
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Chemical Communication and Mate Choice : Investigations into the Meaning of a Fruit Fly Pheromone
- 2005
-
Doctoral thesis (other academic/artistic)abstract
- Chemical signals are the most widely used form of sexual communication throughout the living world. However, there is in general little knowledge about what these signals actually communicate. The role of chemical signals, i.e. pheromones, in sexual behaviour has traditionally been seen as restricted to mate attraction and species recognition. This thesis reviews the evidence for pheromones as indicators of mate quality, and then investigates three important factors for mate quality signals – individual variation, heritability and cost – by using the male pheromone of the lekking fruit fly Drosophila grimshawi as a model.The experiments presented indicate that the pheromone of D. grimshawi has multiple functions, and that these functions vary with social context. Thus, with regard to females, the pheromone seems to act mainly as a species/mate recognition signal, since females show little preference for the amount of pheromone deposited by a male. Moreover, males invest less in pheromone production when subjected to females as compared to when subjected to rival males. However, the pheromone seems to be costly in production since males that invest much in pheromone deposition has a shorter lifespan. This suggests a function for the pheromone in male-male interactions. Males can distinguish their own pheromone depositions from those of a strange male, and also discriminate between pheromone depositions from one and two strange males. This might give them the ability to assess the size of a lek and the competitive capacities of rivals, information that should be useful when optimizing sexual behaviour.In conclusion, the pheromone seems to act as an honest mate/competitor quality signal in some social contexts, and as a non-costly species/mate recognition signal in other. In addition, I show for the first time that a chemical signal has differential fitness costs, and that an insect is able to distinguish between individual odour signatures.
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| 40. |
- Johansson, Fredrik, et al.
(author)
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A Bayesian network approach to threat evaluation with application to an air defense scenario
- 2008
-
In: Proceedings of the 11th International Conference on Information Fusion, FUSION 2008, Cologne, 30 June 2008–3 July 2008. - : IEEE Computer Society. - 9783000248832 - 9783800730926 ; , s. 1352-1358
-
Conference paper (peer-reviewed)abstract
- In this paper, a precise description of the threat evaluation process is presented. This is followed by a review describing which parameters that have been suggested for threat evaluation in an air surveillance context throughout the literature, together with an overview of different algorithms for threat evaluation. Grounded in the findings from the literature review, a threat evaluation system have been developed. The system is based on a Bayesian network approach, making it possible to handle imperfect observations. The structure of the Bayesian network is described in detail. Finally, an analysis of the system’s performance as applied to a synthetic scenario is presented.
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| 41. |
- Johansson, Fredrik, et al.
(author)
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A Comparison between Two Approaches to Threat Evaluation in an Air Defense Scenario
- 2008
-
In: Modeling Decisions for Artificial Intelligence. - Berlin, Heidelberg : Springer Berlin/Heidelberg. - 9783540882688 - 9783540882695 ; , s. 110-121
-
Conference paper (peer-reviewed)abstract
- Threat evaluation is a high-level information fusion problem of high importance within the military domain. This task is the foundation for weapons allocation, where assignment of blue force (own) weapon systems to red force (enemy) targets is performed. In this paper, we compare two fundamentally different approaches to threat evaluation: Bayesian networks and fuzzy inference rules. We conclude that there are pros and cons with both types of approaches, and that a hybrid of the two approaches seems both promising and viable for future research.
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| 42. |
- Johansson, Fredrik, et al.
(author)
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A survivability-based testbed for comparing threat evaluation algorithms
- 2008
-
In: Proceedings of the 2nd Skövde Workshop on Information Fusion Topics (SWIFT 2008). - Skövde : University of Skövde. - 9789163336973 ; , s. 22-24
-
Conference paper (peer-reviewed)abstract
- Threat evaluation is the process in which threat values are assigned to detected targets, based upon the inferred capabilities and intents of the targets to inflict damage to blue force defended assets. This is a high-level information fusion process of high importance, since the calculated threat values are used as input when blue force weapon systems are allocated to the incoming targets, a process often referred to as weapon allocation. Threat values can be calculated from a number of different parameters, such as the position of the closest point of approach (CPA) with respect to blue force defended assets, time required to reach the CPA, the target’s velocity, and its type. A number of algorithms for calculating threat values have been suggested throughout literature, however, criteria to evaluate the performance of such algorithms seem to be lacking. In this paper, we discuss different ways to assess the performance of threat evaluation algorithms. In specific, we describe how threat evaluation algorithms can be compared to each other, using a survivability criterion. Survivability is measured by running the threat evaluation algorithms on simulated scenarios and using the resulting threat values as input to a weapon allocation module. Depending on how well the threat evaluation is performed, the ability of the blue force weapon systems to eliminate the incoming targets will vary (and thereby also the survivability of the defended assets).
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| 43. |
- Johansson, Fredrik, 1968-, et al.
(author)
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An indomethacin-sensitive contraction induced by β-antagonists in guinea pig airways
- 2004
-
In: Canadian Journal of Physiology and Pharmacology. - : Canadian Science Publishing. - 0008-4212 .- 1205-7541. ; 82:6, s. 393-401
-
Journal article (peer-reviewed)abstract
- β-adrenergic receptor (β-AR) antagonists have been associated with increased airway reactivity in asthmatics and potentiation of contractile stimuli in animal models. In the present study, using an in vitro model of tracheal preparations from guinea pigs, we show that the β-AR antagonists propranolol and pindolol induce a smooth muscle contraction. A prerequisite for this contraction is that the airway preparations have been pre-treated with an β-AR agonist. Our data show that the contractile effect of β-AR antagonists is not a simple consequence of reversing the agonist-induced relaxation. Furthermore, the effect seems to be mediated through interaction with β2-ARs since the response is stereo-selective, and the selective β1-AR receptor antagonist atenolol did not induce any contractile response. SQ 29,546, a thromboxane A2 antagonist; MK 886, a lipoxygenase inhibitor; and indomethacin, a cyclooxygenase inhibitor significantly inhibited the contractions of the tracheal preparations induced with propranolol or pindolol. We put forward the hypothesis that the contractile effect of the β-AR antagonist is a consequence of their inverse agonist activity, which is only evident when the receptor population have a higher basal activity. Our results indicate a novel additional explanation for the known side effect, bronchoconstriction, of β-AR antagonist.Key words: beta antagonist, guinea pig trachea, propranolol, formoterol, pindolol, indomethacin.
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| 44. |
- Johansson, Fredrik, 1968-
(author)
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Bronchial hyperresponsiveness of ß-adrenoceptor agonists and antagonists in guinea pig airways
- 2003
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Doctoral thesis (other academic/artistic)abstract
- Asthma is one of the most common diseases in the industrialised countries. The underlying mechanisms are complex and still not fully understood although inflammation of the airways plays an important role. There are to day several types of drugs used in the treatment of asthma such as anti-inflammatory drugs, specific antagonists for inflammatory mediators and bronchodilators. Beta-agonists are the main choice for relaxing airway constriction, however unwanted effects of beta-agonists on patients with asthma has been reported. The betaantagonists that are used for treatment of hypertension and various other conditions also is shown to be deleterious in asthmatics. In the present study we have used guinea pig airways to examine the proposed deleterious effects of beta-agonists and antagonists. We have shown that the (S)-enantiomeric forms of salbutamol and formoterol are able to potentiate cholinergic stimuli and we have shown that the potentiation was indomethacin sensitive in airway preparations of sensitised guinea pigs. We also showed and confirmed that the (R)-enantiomeric forms of salbutamol and formoterol were more potent in relaxing airway smooth muscle contracted with different stimuli compared to the (S)-enantiomers. The betaantagonists propranolol and pindolol were shown to be able to contract tracheal preparations if they had been pre-treated with a beta-agonist and the contraction was not simply a blockade of the beta-adrenoceptor induced relaxation. Propranolol contraction was stereo-selective and (S)-propranolol was more effective in inducing contraction than (R)-propranolol. Moreover, atenolol a betacselective antagonist induced significantly smaller contractions compared to general beta-antagonists. This indicates that the beta2-adrenocepor probably is involved in the beta-antagonist induced contraction. The cyclooxygenase inhibitor indomethacin, the 5-lipoxygenase inhibitor MK886 and a thromboxane A2 antagonist as well as capsaicin reduced the beta-antagonist induced contraction. This indicates that several arachidonic acid products as well as neuropeptides may be involved in the beta-antagonistinduced contraction.The worsening of asthma by beta-antagonists is well known and the risks associated with beta-agonists are discussed, but the mechanisms behind these effects need further clarification. In this thesis some of the possible mechanism have been discussed, further studies are needed in order to get more safe and effective asthma treatment regime.
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| 45. |
- Johansson, Fredrik, et al.
(author)
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Detection of vessel anomalies : A Bayesian network approach
- 2007
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In: Proceedings of the 2007 International Conference on Intelligent Sensors, Sensor Networks and Information Processing (ISSNIP 2007). - : IEEE Computer Society. - 1424415020 - 9781424415021 - 9781424415014 ; , s. 395-400
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Conference paper (peer-reviewed)abstract
- In this paper we describe a data mining approach for detection of anomalous vessel behaviour. The suggested approach is based on Bayesian networks which have two important advantages compared to opaque machine learning techniques such as neural networks: (1) possibility to easily include expert knowledge into the model, and (2) possibility for humans to understand and interpret the learned model. Our approach is implemented and tested on synthetic data, where initial results show that it can be used for detection of single-object anomalies such as speeding.
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| 46. |
- Johansson, Fredrik, et al.
(author)
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Implementation and integration of a Bayesian Network for prediction of tactical intention into a ground target simulator
- 2006
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In: 9th International Conference on Information Fusion. - : IEEE. - 9781424409532
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Conference paper (peer-reviewed)abstract
- Prediction of the enemy's intention is a main issue of threat analysis, and, hence, will be an important part of the C2-systems of tomorrow. A technique that can be useful for this kind of predictions is Bayesian networks (BNs). We have developed a BN for prediction of the enemy's tactical intention, and the implemented BN has been integrated into a ground target simulation framework. The general problem of how to find appropriate prior distributions for BNs has been addressed by developing a tool for data collection, which may make it easier to come up with appropriate prior distributions, by learning conditional probability tables from collected cases, i.e. parameter learning
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| 47. |
- Johansson, Fredrik, et al.
(author)
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Real-time Allocation of Firing Units To Hostile Targets
- 2011
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In: Journal of Advances in Information Fusion. - : ISIF, International Society of Information Fusion. - 1557-6418. ; 6:2, s. 187-199
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Journal article (peer-reviewed)abstract
- The protection of defended assets such as military bases and population centers against hostile targets (e.g., aircrafts, missiles, and rockets) is a highly relevant problem in the military conflicts of today and tomorrow. In order to neutralize threats of this kind, they have to be detected and engaged before causing any damage to the defended assets. We review algorithms for solving the resource allocation problem in real-time, and empirically investigate their performance using the open source testbed SWARD. The reults show that many of the tested algorithms produce high quality solutions for small-scale problems. A novel vaiant of particle swarm optimization seeded with an enhanced greedy algorithm is described and is shown to perform best for large instances of the real-time allocation problem.
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| 48. |
- Johansson-Stenman, Olof, 1966, et al.
(author)
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Costs and Benefits of Electric Vehicles - A 2010 Perspective
- 2002
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Reports (other academic/artistic)abstract
- This paper undertakes a social cost-benefit analysis regarding an increase in the number of electric vehicles in the Swedish transport sector by year 2010. Battery cars are generally found to be socially unprofitable, even though their private life-cycle costs and external costs are lower than those of petrol cars. One important reason for this is that electric vehicles are heavily subsidised' by having, in comparison with taxes on fossil fuel, a very low electricity tax. Hybrid' cars are more likely to be socially profitable, especially for city-based delivery trucks, which may be both privately and socially profitable without subsidies.
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| 49. |
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| 50. |
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