| 1. |
- Johansson, Fredrik
(författare)
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Evaluating the performance of TEWA systems
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- It is in military engagements the task of the air defense to protect valuable assets such as air bases from being destroyed by hostile aircrafts and missiles. In order to fulfill this mission, the defenders are equipped with sensors and firing units. To infer whether a target is hostile and threatening or not is far from a trivial task. This is dealt with in a threat evaluation process, in which the targets are ranked based upon their estimated level of threat posed to the defended assets. Once the degree of threat has been estimated, the problem of weapon allocation comes into the picture. Given that a number of threatening targets have been identified, the defenders need to decide on whether any firing units shall be allocated to the targets, and if so, which firing unit to engage which target. To complicate matters, the outcomes of such engagements are usually stochastic. Moreover, there are often tight time constraints on how fast the threat evaluation and weapon allocation processes need to be executed. There are already today a large number of threat evaluation and weapon allocation (TEWA) systems in use, i.e. decision support systems aiding military decision makers with the threat evaluation and weapon allocation processes. However, despite the critical role of such systems, it is not clear how to evaluate the performance of the systems and their algorithms. Hence, the work in thesis is focused on the development and evaluation of TEWA systems, and the algorithms for threat evaluation and weapon allocation being part of such systems. A number of algorithms for threat evaluation and static weapon allocation are suggested and implemented, and testbeds for facilitating the evaluation of these are developed. Experimental results show that the use of particle swarm optimization is suitable for real-time target-based weapon allocation in situations involving up to approximately ten targets and ten firing units, while it for larger problem sizes gives better results to make use of an enhanced greedy maximum marginal return algorithm, or a genetic algorithm seeded with the solution returned by the greedy algorithm.
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| 2. |
- Hellquist, Björn, et al.
(författare)
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Structures of Solvated Cations of Palladium(II) and Platinum(II) in Dimethyl Sulfoxide, Acetonitrile and Aqueous Solution Studied by EXAFS and LAXS
- 1991
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Ingår i: Acta Chemica Scandinavica. - : Danish Chemical Society. - 0904-213X. ; 45:5, s. 449-455
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Tidskriftsartikel (refereegranskat)abstract
- X-Ray absorption edge and EXAFS spectra of the solvated cations of platinum(II) in water, dimethyl sulfoxide and acetonitrile and of palladium(II) in dimethyl sulfoxide have been recorded and analyzed. The cations are four-coordinated. Pt-O in Pt(H2O)4(2+) is 2.01(1) angstrom and Pt-N in Pt(CH3CN)4(2+) is 2.00(1) angstrom. The dimethyl sulfoxide solvated cations of both platinum and palladium contain two sulfur- and two oxygen-bonded ligands with Pt-O 2.07(2), Pt-S 2.21(2), Pd-O 2.04(2), and Pd-S 2.23(2) angstrom, probably in a square-planar cis-arrangement, as in the solid state. Large-angle X-ray scattering (LAXS) studies of the platinum(II) dimethyl sulfoxide solvated cation in a solution of the triflate salt gave Pt-O 2.07(1) and Pt-S 2.20(1) angstrom and in a solution of the tetrafluoroborate salt Pt-O 2.07(2) and Pt-S 2.21(5) angstrom, in good agreement with the EXAFS results. Neither technique gave any support for axially bound solvent molecules in addition to the four in the assumed square coordination plane.
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| 3. |
- Nystedt, Björn, et al.
(författare)
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The Norway spruce genome sequence and conifer genome evolution
- 2013
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Ingår i: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 497:7451, s. 579-584
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Tidskriftsartikel (refereegranskat)abstract
- Conifers have dominated forests for more than 200 million years and are of huge ecological and economic importance. Here we present the draft assembly of the 20-gigabase genome of Norway spruce (Picea abies), the first available for any gymnosperm. The number of well-supported genes (28,354) is similar to the >100 times smaller genome of Arabidopsis thaliana, and there is no evidence of a recent whole-genome duplication in the gymnosperm lineage. Instead, the large genome size seems to result from the slow and steady accumulation of a diverse set of long-terminal repeat transposable elements, possibly owing to the lack of an efficient elimination mechanism. Comparative sequencing of Pinus sylvestris, Abies sibirica, Juniperus communis, Taxus baccata and Gnetum gnemon reveals that the transposable element diversity is shared among extant conifers. Expression of 24-nucleotide small RNAs, previously implicated in transposable element silencing, is tissue-specific and much lower than in other plants. We further identify numerous long (>10,000 base pairs) introns, gene-like fragments, uncharacterized long non-coding RNAs and short RNAs. This opens up new genomic avenues for conifer forestry and breeding.
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| 4. |
- Holmberg, Lars
(författare)
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Ageing and sexing birds
- 2023
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Ageing and sexing birds require specialist knowledge and training concerning which characteristics to focus on for different species. An expert can formulate an explanation for a classification using these characteristics and, additionally, identify anomalies. Some characteristics require practical training, for example, the difference between moulted and non-moulted feathers, while some knowledge, like feather taxonomy and moulting patterns, can be learned without extensive practical training. An explanation formulated for a classification, by a human, stands in sharp contrast to an explanation produced by a trained neural network. These machine explanations are more an answer to a how-question, related to the inner workings of the neural network, not an answer to a why-question, presenting domain-related characteristics useful for a domain expert. For machine-created explanations to be trustworthy neural networks require a static use context and representative independent and identically distributed training data. These prerequisites do seldom hold in real-world settings. Some challenges related to this are neural networks' inability to identify exemplars outside the training distribution and aligning internal knowledge creation with characteristics used in the target domain. These types of questions are central in the active research field of explainable artificial intelligence (XAI), but, there is a lack of hands-on experiments involving domain experts. This work aims to address the above issues with the goal of producing a prototype where domain experts can train a tool that builds on human expert knowledge in order to produce useful explanations. By using internalised domain expertise we aim at a tool that can produce useful explanations and even new insights for the domain. By working together with domain experts from Ottenby Observatory our goal is to address central XAI challenges and, at the same time, add new perspectives useful to determine age and sex on birds.
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| 5. |
- Grenda, Kinga, 1989, et al.
(författare)
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An analytical approach to elucidate the architecture of polyethyleneimines
- 2022
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Ingår i: Journal of Applied Polymer Science. - : Wiley. - 1097-4628 .- 0021-8995. ; 139:7
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Tidskriftsartikel (refereegranskat)abstract
- Polyethyleneimine (PEI) is a common polymer used in many industrial applications and in research, especially in surface chemistry. It is available in a wide range of molecular weights and different degrees of branching. It is classified as linear or branched and sometimes the term hyperbranched is also used. This description, however, is quite rough, which limits the possibility to correlate the structure of the PEI to its properties. The aim of this study is to provide analytical tools to characterize the polymer at a level of detail not normally provided by the supplier of PEI. To this end, five commercially available polyethyleneimines were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and nuclear magnetic resonance spectroscopy to gain insight into the structure and the functional groups present in the polymers. Quantitative 13C NMR analysis turned out to be particularly useful, revealing the degree of branching of the polymer based on the ratio of primary, secondary, and tertiary amino groups.
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| 6. |
- Holmberg, Lars
(författare)
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A Conceptual Approach to Explainable Neural Networks
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The success of neural networks largely builds on their ability to create internal knowledge representations from real-world high-dimensional data, such as images, sound, or text. Approaches to extract and present these representations, in order to explain a neural network’s decision, is an active and multifaceted research field. To gain a deeper understanding of a central aspect of this field, we performed a targeted literature review focusing on research that aims to associate internal representations with human understandable concepts. By using deductive nomological explanations combined with causality theories as an analytical lens, we analyse nine carefully selected research papers. We find our analytical lens, the explanation structure and causality, useful to understand what can be expected, and not expected, from explanations inferred from neural networks. The analysis additionally uncovers an ambiguity in the reviewed literature related to the goal: is it (a) understanding the ML model, (b) the training data or (c) actionable explanations that are true-to-the-domain?
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| 7. |
- Holmberg, Lars
(författare)
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Human In Command Machine Learning
- 2021
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Machine Learning (ML) and Artificial Intelligence (AI) impact many aspects of human life, from recommending a significant other to assist the search for extraterrestrial life. The area develops rapidly and exiting unexplored design spaces are constantly laid bare. The focus in this work is one of these areas; ML systems where decisions concerning ML model training, usage and selection of target domain lay in the hands of domain experts. This work is then on ML systems that function as a tool that augments and/or enhance human capabilities. The approach presented is denoted Human In Command ML (HIC-ML) systems. To enquire into this research domain design experiments of varying fidelity were used. Two of these experiments focus on augmenting human capabilities and targets the domains commuting and sorting batteries. One experiment focuses on enhancing human capabilities by identifying similar hand-painted plates. The experiments are used as illustrative examples to explore settings where domain experts potentially can: independently train an ML model and in an iterative fashion, interact with it and interpret and understand its decisions. HIC-ML should be seen as a governance principle that focuses on adding value and meaning to users. In this work, concrete application areas are presented and discussed. To open up for designing ML-based products for the area an abstract model for HIC-ML is constructed and design guidelines are proposed. In addition, terminology and abstractions useful when designing for explicability are presented by imposing structure and rigidity derived from scientific explanations. Together, this opens up for a contextual shift in ML and makes new application areas probable, areas that naturally couples the usage of AI technology to human virtues and potentially, as a consequence, can result in a democratisation of the usage and knowledge concerning this powerful technology.
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| 8. |
- Andersson Trojer, Markus, 1981, et al.
(författare)
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Use of microcapsules as controlled release devices for coatings
- 2015
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Ingår i: Advances in Colloid and Interface Science. - : Elsevier BV. - 0001-8686. ; 222, s. 18-43
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Tidskriftsartikel (refereegranskat)abstract
- Biofouling of surfaces is a considerable problem in many industrial sectors and for the public community in general. The problem is usually approached by the use of functional coatings and most of such antifouling coatings rely on the effect of biocides. However, a substantial drawback is the poor control over the release of the biocide as well as its degradation in the paint. Encapsulation of the biocides in microcapsules is a promising approach that may overcome some of the problems associated with the more traditional ways of incorporating the antifouling agent into the formulation. In this review, we summarize more than a decade of microcapsule research from our lab as well as from other groups working on this topic. Focus will be on two coacervation-based encapsulation techniques; the internal phase separation method and the double emulsion method, which together enable the encapsulation of a broad spectrum of biocides with different physicochemical properties. The release of the biocide from core-shell particles and from encapsulated biocides in coatings is treated in detail. The release behaviour is interpreted in terms of the physicochemical properties of the core-shell particle and the coating matrix. In addition, special attention is given to the experimental release methodology and the implementation of proper diffusion models to describe the release. At the end of the review examples of antifouling properties of some coatings against common biofoulers are presented.
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| 9. |
- Rosén, Hanna, et al.
(författare)
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Sorting of Von Willebrand factor to lysosome-related granules of haematopoietic cells
- 2004
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Ingår i: Biochemical and Biophysical Research Communications. - : Elsevier BV. - 1090-2104 .- 0006-291X. ; 315:3, s. 671-678
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this work was to investigate sorting mechanisms of von Willebrand factor (VWF) when expressed in haematopoietic cells. The processing and sorting of both the wild-type VWF and a multimerization defective propeptide-mutant (VWFm) were investigated after expression in the 32D cell line. Normal proteolytic processing was observed for both proteins, however the processing of VWFm was much slower and a large portion was unprocessed. Results from subcellular fractionation and immunoelectron microscopy confirmed that a part of VWF, but not VWFm, was targeted to lysosome-related granules. Partial constitutive secretion was also observed for all forms of VWF and VWFm. Inhibition of acidification by chloroquine blocked VWF processing but allowed unprocessed pro-VWF targeting to dense organelles. In conclusion, our observations are consistent with VWF multimerization being of importance in cellular retention and targeting to lysosome-related organelles in haematopoietic cells, suggesting a role of protein aggregation for sorting in these cells. (C) 2004 Elsevier Inc. All rights reserved.
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| 10. |
- Sheng, Ming, 1981-
(författare)
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Regulation of energy balance in Caenorhabditis elegans
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Obesity is a medical condition in which excess body fat has been accumulated. It is most commonly caused by imbalance between energy intake and energy expenditure (lack of physical activity and lower metabolic rate, etc.). The control of energy metabolism involves multiple tissues and signalling pathways and there is a great need for further understanding of these different interactions.In this study, I use Caenorhabditis elegans to study these complex pathways at the level of a whole organism. The downstream target of mTOR, p70 S6 kinase (S6K), has been implicated in the phosphorylation of multiple substrates and the regulation of growth and metabolism. In this study the worm homolog of S6K, rsks-1, found to be important for fat metabolism. Previous work in our lab found that RSKS-1::GFP is expressed at high levels in a set of sensory neurons and upregulated in ASJ, ASE and BAG sensory neurons in starved worms or mutants with low insulin activity. In this study, I found that the upregulation of rsks-1 expression was affected by serotonin, but not by the other neurotransmitters. Combined with the result that rsks-1 is required for the expression of TGFβ and insulin in ASI, rsks-1 may control dietary sensing by affecting insulin and TGFβ signalling within nervous system. Quantification of fat accumulation by TLC/GC revealed that in comparison to wild type worms, rsks-1 mutants have more than two-fold higher levels of triglycerides. This was confirmed by FT-IR microspectroscopy analysis. rsks-1 mutants also contain disproportionately high levels of C16:1n9 and C18:1n9 lipids compared with wild type worms. Genetic analysis has shown that rsks-1 acts either downstream of, or in parallel to the insulin and TGFβ pathways to affect fat levels. My studies showed that rsks-1 affects fat metabolism by influencing mRNA levels of genes encoding proteins in the β-oxidation pathway. Combined with defects in dietary sensing, fatty acid absorption, fertility and mitochondria function, the loss of rsks-1 activity induced much more energy storage than wild type by making a profound metabolic shift. These results are consistent with the metabolomics data analysis. Tissue specific RNAi showed that rsks-1 was required in many different tissues to regulate fat metabolism. Taken together, it can be concluded that RSKS-1 activity is needed for co-ordination of metabolic states in C. elegans. In order to understand more about the physiology behind fat accumulation, I analysed a mutant, aex-5, that has significantly lowered lipid levels. I found that this defect is associated with a significant reduction in the rate at which dietary fatty acids are taken up from the intestinal lumen. The aex-5 gene, which encodes a Kex2/subtilisin-family, Ca2+-sensitive proprotein convertase, is required for a discrete step in an ultraradian rhythmic phenomenon called the defecation motor program (DMP). Combined with other results, we conclude that aex-5 and other defecation genes may affect fat uptake by promoting the correct distribution of acidity within the intestinal lumen.This dissertation also described how to use Fourier transform infrared (FT-IR) microspectroscopy to detect lipids, proteins and carbohydrates directly in single worm. In conclusion, in this thesis I have uncovered several components that play roles in dietary sensing, fatty acid synthesis, adiposity regulation and fatty acid absorption in C. elegans.
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