| 1. |
- Bergkvist, Lisa, et al.
(författare)
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Carbon Sequestration Potential f Agroforestry Systems For Phytoremediation In Chinandega, Nicaragua
- 2018
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Ingår i: Linnaeus Eco-Tech 2018. ; , s. 211-211
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Greenhouse gases in the atmosphere have increased to earlier unrecorded levels, causing global climate change that increases GMT and threaten ecosystems and livelihoods. IPCC report suggest that agroforestry offers considerable carbon sequestration (c seq.) potential, especially for developing countries. The purpose of this study is to estimate the c seq. potential in different agroforestry systems suitable in Chinandega, Nicaragua - a deforested region where the ground is polluted by toxaphene and other POP:s. Three scenarios where studied; Shading system using Tectona grandis and Pogostemon cablin; Alley cropping using Erythrina poeppigiana and Ricinus communis and Silvopasture using Cordia alliodora and Brachiaria ruziziensis, the last scenario being divided into two subscenarios; unmanaged (grazed) and managed (harvested) grass. Calculations were performed using the modelling program CO2FIX v. 3.2, with a runtime of 100 years and assuming deforested area with no previous land use. Results show a significantly higher c seq. potential in Shading system (168/217 MgC/ha). Alley cropping yields 71 MgC/ha and Silvopasture results in 80/84 MgC/ha unmanaged and 65/70 MgC/ha managed. The higher number includes products from harvest. All scenarios show fluctuations over time due to thinning and harvesting practices. Phytoremediation potential of POPs has been shown in Ricinus communis and grass species. Soil c seq. is especially important to consider in longterm scenarios as this c seq. can be sustained over longer time. The inclusion of crop residue, the effect of grazing animals or changes in density of trees and crops and environmental fate of the toxic compounds need further assessment before considering large scale applications. Agroforestry practices could contribute to several benefits, including climate change mitigation and phytoremediation.
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| 2. |
- Bäckström, Christer, et al.
(författare)
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From Macro Plans to Automata Plans
- 2012
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Ingår i: ECAI 2012. 20th European Conference on Artificial Intelligence, 27-31 2012, August, Montpellier, France. - 9781614990970 - 9781614990987 ; , s. 91-96
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Konferensbidrag (refereegranskat)abstract
- Macros have a long-standing role in planning as a tool for representing repeating subsequences of operators. Macros are useful both for guiding search towards a solution and for representing plans compactly. In this paper we introduce automata plans which consist of hierarchies of finite state automata. Automata plans can be viewed as an extension of macros that enables parametrization and branching. We provide several examples of the utility of automata plans, and prove that automata plans are strictly more expressive than macro plans. We also prove that automata plans admit polynomialtime sequential access of the operators in the underlying “flat” plan, and identify a subset of automata plans that admit polynomial-time random access. Finally, we compare automata plans with other representations allowing polynomial-time sequential access.
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| 3. |
- Bäckström, Christer, et al.
(författare)
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Macros, Reactive Plans and Compact Representations
- 2012
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Ingår i: ECAI 2012. 20th European Conference on Artificial Intelligence 27-31 August 2+12, Montpellier, France. - 9781614990970 - 9781614990987 ; , s. 85-90
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Konferensbidrag (refereegranskat)abstract
- The use and study of compact representations of objects is widespread in computer science. AI planning can be viewed as the problem of finding a path in a graph that is implicitly described by a compact representation in a planning language. However, compact representations of the path itself (the plan) have not received much attention in the literature. Although both macro plans and reactive plans can be considered as such compact representations, little emphasis has been placed on this aspect in earlier work. There are also compact plan representations that are defined by their access properties, for instance, that they have efficient random access or efficient sequential access. We formally compare two such concepts with macro plans and reactive plans, viewed as compact representations, and provide a complete map of the relationships between them.
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| 4. |
- Jonsson, Anders, et al.
(författare)
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When Acyclicity is not Enough: Limitations of the Causal Graph
- 2013
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Ingår i: Proceedings of the Twenty-Third International Conference on Automated Planning and Scheduling. - : AAAI Press. - 9781577356097 ; , s. 117-125
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Konferensbidrag (refereegranskat)abstract
- Causal graphs are widely used in planning to capture the internal structure of planning instances. In the past, causal graphs have been exploited to generate hierarchical plans, to compute heuristics, and to identify classes of planning instances that are easy to solve. It is generally believed that planning is easier when the causal graph is acyclic. In this paper we show that this is not true in the worst case, proving that the problem of plan existence is PSPACE-complete even when the causal graph is acyclic. Since the variables of the planning instances in our reduction are propositional, this result applies to STRIPS planning with negative pre-conditions. Having established that planning is hard for acyclic causal graphs, we study a subclass of planning instances with acyclic causal graphs whose variables have strongly connected domain transition graphs. For this class, we show that plan existence is easy, but that bounded plan existence is hard, implying that optimal planning is significantly harder than satisficing planning for this class.
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| 5. |
- Schomacker, Anders, et al.
(författare)
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THE ACTIVE DRUMLIN FIELD AT THE MÚLAJÖKULL SURGE-TYPE GLACIER, ICELAND – GEOMORPHOLOGY AND SEDIMENTOLOGY
- 2011
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Ingår i: Geological Society of America abstracts with programs Minnespolis 2011.
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Konferensbidrag (refereegranskat)abstract
- Recent marginal retreat of Múlajökull, a surge-type, outlet glacier of the Hofsjökull ice cap, central Iceland, has revealed a drumlin field consisting of over 50 drumlins. The drumlins are 90–320 m long, 30–105 m wide, 5–10 m in relief, and composed of multiple beds of till deposited by lodgement and bed deformation. The youngest till layer truncates the older units with an erosion surface that parallels the drumlin form. Thus, the drumlins are built up and formed by a combination of subglacial depositional and erosional processes. Field evidence suggests each till bed to be associated with individual, recent surges. We consider the drumlin field to be active in the sense that the drumlins are shaped by the current glacial regime. To our knowledge, the Múlajökull field is the only known active drumlin field and is, therefore, a unique analogue to Pleistocene drumlin fields.
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| 6. |
- Johansson, Björn, 1975, et al.
(författare)
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Sustainable Production by Integrating Business Models of Manufacturing and Recycling Industries
- 2011
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Ingår i: Proceedings of the 18th CIRP International Conference on Life Cycle Engineering. - 3642196918 ; , s. 723-
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Konferensbidrag (refereegranskat)abstract
- Future raw material shortage, high price levels and environmental regulations requires increased reuse of materials andcomponents. This will substantially influence conditions for both manufacturing and recycling industries, which need toinnovate their business models. Our hypothesis is that an integrated co-operation between organizations within these industries, employing symbiotic business models will increase the profitability and reduce the total environmental impact. Findings from interaction with manufacturing and recycling industries using a business model framework as baseline are presented. Results indicate that profit and decreased environmental effects can be achieved through symbiotic business models, but further development and implementation is needed.
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| 7. |
- Jonsson, Sigurdur, et al.
(författare)
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Monte Carlo studies of protein aggregation
- 2012
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Ingår i: Physics Procedia. - : Elsevier BV. - 1875-3892. ; 34, s. 49-54
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Konferensbidrag (refereegranskat)abstract
- The disease-linked amyloid beta (A beta) and alpha-synuclein (alpha S) proteins are both fibril-forming and natively unfolded in free monomeric form. Here, we discuss two recent studies, where we used extensive implicit solvent all-atom Monte Carlo (MC) simulations to elucidate the conformational ensembles sampled by these proteins. For alpha S, we somewhat unexpectedly observed two distinct phases, separated by a clear free-energy barrier. The presence of the barrier makes alpha S, with 140 residues, a challenge to simulate. By using a two-step simulation procedure based on flat-histogram techniques, it was possible to alleviate this problem. The barrier may in part explain why fibril formation is much slower for alpha S than it is for A beta.
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| 8. |
- Waller, Judith, et al.
(författare)
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Measurements of carbon dioxide fluxes over an oligotrophic Boreal river in northern Scandinavia
- 2018
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Ingår i: Book of abstracts : Linnaeus ECO-TECH '18. - Kalmar : Linnaeus University. - 9789188898289
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Carbon dioxide (CO2), as one of the major anthropogenic greenhouse gases, is widely acknowledged to contribute to global warming and climate change. Historically, the major focus on the role of the aquatic environment in the carbon cycle has been on the atmosphere-ocean exchange. More recent findings suggest the importance of freshwater (lakes, rivers and streams) as a source for atmospheric CO2. The freshwater contribution is, however, poorly understood, mainly due to a paucity of data, especially from running waters.To address this issue, eddy covariance (EC) measurements in a large boreal river in Northern Sweden (Indalsälven), are being made as part of a two-year long continual study of the carbon dioxide emissions between the air and water. This is one of the first known studies of its kind where EC measurements are conducted in a river setting. Continual data acquisition began in April 2018, monitoring a variety of general meteorological parameters, turbulent emissions of carbon dioxide, latent, and sensible heat, together with water-side measurements of CO2. The aim of the study is to investigate the temporal control on river carbon dioxide emissions covering timescales from hours to seasons.This paper describes the ongoing work, and reports on the present status of the project. The primary focus lies on data that indicates a dependence of carbon dioxide flux on wind-speed. Wind speed demonstrates a positive correlation with the measured emissions, with the highest emissions measured corresponding to the directions where the upwind distance to land was greatest, indicating that the wind-generated turbulence has a strong influence on the carbon dioxide emissions over a boreal river.
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| 9. |
- Gustafsson, Mats, et al.
(författare)
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Physical bounds on the partial realized gain
- 2010
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Ingår i: [Host publication title missing]. ; , s. 1-6
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Konferensbidrag (refereegranskat)abstract
- An antenna identity, derived from the forward scattering sum rule, shows that the partial realized gain of an antenna is related to the polarizability of the antenna structure. The partial realized gain contains the mismatch, directivity, efficiency, and polarization properties of the antenna. The antenna identity expresses how the performance depends on the electrical size and shape of the antenna structure. It is also the starting point for several antenna bounds. In this paper, the identity, its associated physical bounds, and computational aspects of the polarizability dyadics are discussed.
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| 10. |
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