| 1. |
- Berglund, Martin, 1981-, et al.
(författare)
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Shuffled languages : representation and recognition
- 2013
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Ingår i: Theoretical Computer Science. - : Elsevier. - 0304-3975 .- 1879-2294. ; 489-490, s. 1-20
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Tidskriftsartikel (refereegranskat)abstract
- Language models that use interleaving, or shuffle, operators have applications in various areas of computer science, including system verification, plan recognition, and natural language processing. We study the complexity of the membership problem for such models, in other words, how difficult it is to determine if a string belongs to a language or not. In particular, we investigate how interleaving can be introduced into models that capture the context-free languages.
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| 2. |
- Björklund, Henrik, et al.
(författare)
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Compression of finite-state automata through failure transitions
- 2014
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Ingår i: Theoretical Computer Science. - : Elsevier. - 0304-3975 .- 1879-2294. ; 557, s. 87-100
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Tidskriftsartikel (refereegranskat)abstract
- Several linear-time algorithms for automata-based pattern matching rely on failure transitions for efficient back-tracking. Like epsilon transitions, failure transition do not consume input symbols, but unlike them, they may only be taken when no other transition is applicable. At a semantic level, this conveniently models catch-all clauses and allows for compact language representation.This work investigates the transition-reduction problem for deterministic finite-state automata (DFA). The input is a DFA A and an integer k. The question is whether k or more transitions can be saved by replacing regular transitions with failure transitions. We show that while the problem is NP-complete, there are approximation techniques and heuristics that mitigate the computational complexity. We conclude by demonstrating the computational difficulty of two related minimisation problems, thereby cancelling the ongoing search for efficient algorithms.
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| 3. |
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| 4. |
- Ahnström, Johan, et al.
(författare)
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Farmers' Interest in Nature and Its Relation to Biodiversity in Arable Fields
- 2013
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Ingår i: International Journal of Ecology. - : Hindawi Publishing Corporation. - 1687-9708 .- 1687-9716.
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Tidskriftsartikel (refereegranskat)abstract
- Biodiversity declines in farmland have been attributed to intensification of farming at the field level and loss of heterogeneity at the landscape level. However, farmers are not solely optimizing production; their actions are also influenced by social factors, tradition and interest in nature, which indirectly influence biodiversity but rarely are incorporated in studies of farmland biodiversity. We used social science methods to quantify farmers’ interest in nature on 16 farms with winter wheat fields in central Sweden, and combined this with biodiversity inventories of five organism groups (weeds, carabid beetles, bumblebees, solitary bees, and birds) and estimates of landscape composition andmanagement intensity at the field level.Agricultural intensity,measured as crop density, and farmers’ interest in nature explained variation in biodiversity, measured as the proportion of the regional species richness found on single fields. Interest in nature seemed to incorporate many actions taken by farmers and appeared to be influenced by both physical factors, for example, the surrounding landscape, and social factors, for example, social motivations.This study indicates that conservation of biodiversity in farmland, and design of new agri-environmental subsidy systems, would profit from taking farmers’ interest in nature and its relation to agricultural practices into account.
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| 5. |
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| 6. |
- Berglund, Martin, et al.
(författare)
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Recognizing shuffled languages
- 2011
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Ingår i: Language and Automata Theory and Applications. - Berlin, Heidelberg : Springer Berlin/Heidelberg. - 9783642212536 ; , s. 142-154
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Konferensbidrag (refereegranskat)abstract
- Language models that use interleaving, or shuffle, operators have applications in various areas of computer science, including system verification, plan recognition, and natural language processing. We study the complexity of the membership problem for such models, i.e., how difficult it is to determine if a string belongs to a language or not. In particular, we investigate how interleaving can be introduced into models that capture the context-free languages.
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| 7. |
- Björklund, Johanna, 1978-, et al.
(författare)
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Aspects of plan operators in a tree automata framework
- 2012
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Ingår i: 2012 15th International Conference on Information Fusion (FUSION). - : IEEE. - 9780982443842 - 9781467304177 ; , s. 1462-1467
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Konferensbidrag (refereegranskat)abstract
- Plan recognition addresses the problem of inferring an agents goals from its action. Applications range from anticipating care-takers’ needs to predicting volatile situations. In this contribution, we describe a prototype plan recognition system that is based on the well-researched theory of (weighted) finite tree automata. To illustrate the system’s capabilities, we use data gathered from matches in the real-time strategy game StarCraft II. Finally, we discuss how more advanced plan operators can be accommodated for in this framework while retaining computational efficiency by taking after the field of formal model checking and over-approximating the target language.
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| 8. |
- Björklund, Johanna, 1961-, et al.
(författare)
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Assessing ecosystem services in perennial intercropping systems : participatory action research in Swedish modern agrofores
- 2014
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Ingår i: Farming systems facing global challenges. - : IFSA Europe, Leibniz-Centre for Agricultural Landscape Research (ZALF), Humboldt-Universität zu Berlin. ; , s. 112-113, s. 1950-1959
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The focus of this paper is on how to assess ecosystem services in complex agroforestry systems using a case of edible forest gardens. Benefits of doing these assessments in a participatory learning and action research (PLAR) context are elaborated, as well as difficulties and questions that this has raised. The PLAR group comprised farmers on 13 smallholdings, researchers and a facilitator, which through collaboration and participatory methods have developed a general design of a forest garden, 60 m2 in size and established it on all 13 participating farms. Important values of the work are that ecosystem services are related to specific local contexts and that methodology for multi-criteria assessments of the generation of ecosystem services on a farm scale are being developed. Farmers engaged in formulating research questions, development of field trial designs, sampling and analysis of results improves the relevance and quality of the research as well as advance the adoption of new knowledge.
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| 9. |
- Björklund, Johanna, 1961-, et al.
(författare)
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Assessing multifunctionality in relation to resource use : a holistic approach to measure efficiency, developed by participatory research
- 2012
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Ingår i: Methods and procedures for building sustainable farming systems. - Dordrecht : Springer Netherlands. - 9789400750036 - 9789400750029 ; , s. 161-173
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Bokkapitel (refereegranskat)abstract
- Today’s intensive agriculture needs to be transformed into sustainable production of food, and this process requires good tools that can assess whether an action is leading towards this in the long term. A critical issue is what optimal yield comprises in terms of other functions of agriculture, as higher yields might lead to e.g. a reduction in biodiversity or soil carbon. In this study, emergy analysis and footprinting were combined to assess and illustrate the total resource use caused by a farming activity (milk production) and to identify the renewable fraction of this resource use. The total efficiency was defined as a function of the resource use and the multifunctionality of production. The classification of ecosystem services in the Millennium Ecosystem Assessment (MA) was used as the basis for ranking multifunctionality. The results were expressed in the form of ecosystem bundles for the four MA categories (provisioning, supporting, regulating and cultural functions). Three scenarios with different degrees of input intensity and milk production were constructed and compared with the current production mode. The ratio of local renewable resource use to total resource use differed greatly between the different production strategies, being 1:3 for a self-sufficient organic farm and 1:14 for a conventional farm with maximum milk yield. Milk production was five-fold higher on the conventional farm, while generation of ecosystem services increased with increasing self-sufficiency under the local conditions prevailing in the study. Ecosystem services in all categories except provisioning were ranked higher when self-sufficiency increased.
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| 10. |
- Björklund, Johanna, 1961-, et al.
(författare)
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Ecosystem-based agriculture combining production and conservation : a viable way to feed the world in the long term?
- 2012
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Ingår i: Journal of Sustainable Agriculture. - : Taylor & Francis. - 1044-0046 .- 1540-7578. ; 36:7, s. 824-855
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Tidskriftsartikel (refereegranskat)abstract
- This study analyzed examples of sustainable ecosystem-based agriculture where management methods supported livelihoods of smallholders while at the same time local ecosystem services were enhanced in Ethiopia, Brazil, and the Philippines. Participation by farmers and collective actions were found to be a crucial driving force, as local specific knowledge and “learning by doing” were main components of the development. Social cohesion, particularly through associations and cooperatives, and improved marketing opportunities were also important drivers. Furthermore, recognition by authorities at all levels was perceived as crucial. Effects of climate change, insecure property rights, and political instability were potential threats. The possibilities of such systems to be scaled up beyond self-sufficiency raised further questions.
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| 11. |
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| 12. |
- Björklund, Johanna, 1978-, et al.
(författare)
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MAT Learning of Universal Automata
- 2013
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Ingår i: Language and Automata Theory and Applications. - Berlin, Heidelberg : Springer Berlin/Heidelberg. - 9783642370632 - 9783642370649 ; , s. 141-152
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Konferensbidrag (refereegranskat)abstract
- A MAT learning algorithm is presented that infers the universal automaton (UA) for a regular target language, using a polynomial number of queries with respect to that automaton. The UA is one of several canonical characterizations for regular languages. Our learner is based on the concept of an observation table, which seems to be particularly fitting for this computational model, and the necessary notions and definitions are adapted from the literature to the case of UA.
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| 13. |
- Björklund, Johanna, et al.
(författare)
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Simulation relations for pattern matching in directed graphs
- 2013
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Ingår i: Theoretical Computer Science. - : Elsevier. - 0304-3975 .- 1879-2294. ; 485, s. 1-15
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Tidskriftsartikel (refereegranskat)abstract
- We consider the problem of finding the occurrences of a pattern tree t in a directed graph g, and propose two algorithms, one for preprocessing and one for searching for t in g. It is assumed that the object graph itself is large and static, and that the pattern tree is small and frequently updated. To model varying abstraction levels in the data, we work with partially ordered alphabets and compute simulation relations rather than equivalence relations. In particular, vertices and edges are labelled with elements from a pair of preorders instead of unstructured alphabets. Under the above assumptions, we obtain a search algorithm that runs in time O(height (t) . vertical bar t vertical bar . vertical bar(V-g(+/-)t/R-g(+/-)t vertical bar(2)) where vertical bar (V-g(+/-)t/R-g(+/-)t)vertical bar is the number of equivalence classes in the coarsest simulation relation R-g(+/-)t on the graph g((+/-))t, the disjoint union of g and t. This means that the size of the object graph only affects the running time of the search algorithm indirectly, because of the groundwork done by the preprocessing routine in time O(k . vertical bar g vertical bar . vertical bar(V-g/R-g)vertical bar(2)), where vertical bar(V-g/R-g) is the number of equivalence classes in the coarsest simulation relation R-g on g, taking k = vertical bar V-g vertical bar(2) in the general case and k = height (g) if g is acyclic.
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| 14. |
- Helmersson-Karlqvist, Johanna, et al.
(författare)
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24-Hour ambulatory blood pressure associates inversely with prostaglandin F-2 alpha, interleukin-6 and F-2-isoprostane formation in a Swedish population of older men
- 2012
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Ingår i: International Journal of Clinical and Experimental Medicine. - 1940-5901. ; 5:2, s. 145-153
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Tidskriftsartikel (refereegranskat)abstract
- Vasoconstrictive prostaglandins (PGs), such as PGF(2 alpha), F-2-isoprostanes, and systemic inflammation may be involved in the physiological regulation of blood pressure (BP) and the pathophysiology leading to hypertension. However, studies evaluating these parameters and BP in human populations are sparse. We analysed the cross-sectional associations between 24-hour ambulatory BP and urinary 15-keto-dihydro-PGF(2 alpha) (indicator of PG-mediated vasoconstriction and inflammation), plasma interleukin-6 (IL-6), C-reactive protein (CRP), serum amyloid A (SAA) and urinary F-2-isoprostanes (indicator of vasoconstriction and oxidative stress) in 619 men in a Swedish older population (Uppsala Longitudinal Study of Adult Men, age 78 years). Both systolic and diastolic 24-hour BP correlated inversely with concentrations of 15-keto-dihydro-PGF(2 alpha) (P < 0.01) and F-2-isoprostanes (P< 0.01) independent on other cardiovascular risk factors. Additionally, diastolic 24-hour BP inversely correlated with plasma IL-6 (P< 0.05) and 24-hour pulse pressure showed a positive linear correlation with IL-6, CRP and SAA. In conclusion, high BP is associated with decreased formation of vasoconstrictive PGF(2 alpha) and F-2-isoprostanes in this population of older men. These findings, although unlike our original hypothesis, might have an important physiological function which needs to be further evaluated.
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| 15. |
- Milestad, Rebecka, et al.
(författare)
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Enhancing Adaptive Capacity in Food Systems : Learning at Farmers' Markets in Sweden
- 2010
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Ingår i: Ecology and Society. - 1708-3087. ; 15:3, s. 29-
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Tidskriftsartikel (refereegranskat)abstract
- This article examines how local food systems in the form of farmers' markets can enhance adaptive capacity and build social-ecological resilience. It does this by exploring the learning potential among farmers and customers. Learning can enable actors to adapt successfully and thus build adaptive capacity. Three forms of learning are investigated: instrumental, communicative, and emancipatory. These forms of learning constitute the foundation for lasting changes of behaviors. Local food systems are characterized by close links and opportunities for face-to-face interactions between consumers and producers of food, and are also institutions where farmers and customers can express and act upon their ethical values concerning food. However, local food systems are still a marginal phenomenon and cannot be accessed by all consumers. Interviews were held with customers and farmers, and the interactions between farmers and customers were observed at two farmers' markets in Sweden. Customers and farmers were found to learn and adapt to each other due to the opportunities offered by the farmers' markets. We found that farmers and customers learned in the instrumental and communicative domains, but could not confirm emancipatory learning. We concluded that the feedback between customers and farmers offers the potential for learning, which in turn contributes to adaptive capacity. This can be a driving force for building resilience in the food system.
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| 16. |
- Milestad, Rebecka, et al.
(författare)
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Essential multiple functions of farms in rural communities and landscapes
- 2011
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Ingår i: Renewable Agriculture and Food Systems. - 1742-1705 .- 1742-1713. ; 26:2, s. 137-148
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Tidskriftsartikel (refereegranskat)abstract
- As farms are consolidated into larger operations and small farms close down for economic reasons, rural areas lose ecological, social and economic functions related to farming. Biodiversity and scenic, open-vista landscapes are lost as fields are left unmanaged. Social and economic benefits such as local job opportunities and meeting places disappear. Four Swedish rural communities were examined to increase our understanding of the functions that a diverse agriculture provides and which of these are lost as farms cease operation and overall rural social capital is depleted. Workshops and interviews with village action groups and with farmers were carried out. Both groups identified key functions from farming that are important to the rural community, such as production of food and fiber, businesses and jobs, human services, local security, ecosystem services such as nutrient cycling and biodiversity, and functions pertaining to quality of life. Several ways in which village action groups can support agriculture were identified that current industrial agriculture and even agri-environmental schemes fail to achieve. These include organizing local meeting places, encouraging local processing and consumption and supporting farmers in their work. We conclude that agriculture and village action groups match well in community development and that policies supporting this match would be useful.
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| 17. |
- Tunon, Håkan, et al.
(författare)
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Grattis Moder Jord!
- 2010
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Ingår i: Svenska Dagbladet/Brännpunkt. ; 22 april 2010
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 18. |
- Valkonen, Janne, et al.
(författare)
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Disruption or aposematism? : Significance of dorsal zigzag pattern of European vipers
- 2011
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Ingår i: Evolutionary Ecology. - : Springer Science and Business Media LLC. - 0269-7653 .- 1573-8477. ; 25:5, s. 1047-1063
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Tidskriftsartikel (refereegranskat)abstract
- European vipers (genus Vipera) are venomous and often have a distinctive dorsal zigzag pattern. The zigzag pattern of vipers has been suggested to be an example of disruptive colouration which reduces the detectability of a snake. However, recent studies suggest that the patterns have an aposematic function, although those experiments did not exclude the possibility of disruptive colouration. We used plasticine replicas of snakes to examine whether the zigzag pattern of European vipers provides protection from avian predator attacks via disruptive or aposematic function, or if the zigzag pattern might simultaneously serve both antipredatory functions. Experiments were conducted in the Coto Donana National Park southern Spain. In the experiment, predation pressure caused by birds was compared between zigzag pattern (patterns were painted with and without disruptive effect i.e. breaking body outline or not), classical disruptive colouration (non-randomly placed patterns that breaks body outline) and control markings (replicas with length wise stripes and models without painted pattern) on natural and controlled backgrounds. We found that zigzag patterned snake replicas suffered less predation than striped ones regardless of the background, providing further evidence that the zigzag pattern of European vipers functions as a warning signal against predators. However, we did not find evidence that the zigzag pattern involves a disruptive effect.
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| 19. |
- Valkonen, Janne K., et al.
(författare)
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Variation in predator species abundance can cause variable selection pressure on warning signaling prey
- 2012
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Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 2:8, s. 1971-1976
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Tidskriftsartikel (refereegranskat)abstract
- Predation pressure is expected to drive visual warning signals to evolve toward conspicuousness. However, coloration of defended species varies tremendously and can at certain instances be considered as more camouflaged rather than conspicuous. Recent theoretical studies suggest that the variation in signal conspicuousness can be caused by variation (within or between species) in predators' willingness to attack defended prey or by the broadness of the predators' signal generalization. If some of the predator species are capable of coping with the secondary defenses of their prey, selection can favor reduced prey signal conspicuousness via reduced detectability or recognition. In this study, we combine data collected during three large-scale field experiments to assess whether variation in avian predator species (red kite, black kite, common buzzard, short-toed eagle, and booted eagle) affects the predation pressure on warningly and non-warningly colored artificial snakes. Predation pressure varied among locations and interestingly, if common buzzards were abundant, there were disadvantages to snakes possessing warning signaling. Our results indicate that predator community can have important consequences on the evolution of warning signals. Predators that ignore the warning signal and defense can be the key for the maintenance of variation in warning signal architecture and maintenance of inconspicuous signaling.
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| 20. |
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| 21. |
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