| 1. |
- Calatayud, Joaquín, et al.
(författare)
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Exploring the solution landscape enables more reliable network community detection
- 2019
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Ingår i: Physical review. E. - 2470-0045 .- 2470-0053. ; 100:5
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Tidskriftsartikel (refereegranskat)abstract
- To understand how a complex system is organized and functions, researchers often identify communities in the system's network of interactions. Because it is practically impossible to explore all solutions to guarantee the best one, many community-detection algorithms rely on multiple stochastic searches. But for a given combination of network and stochastic algorithms, how many searches are sufficient to find a solution that is good enough? The standard approach is to pick a reasonably large number of searches and select the network partition with the highest quality or derive a consensus solution based on all network partitions. However, if different partitions have similar qualities such that the solution landscape is degenerate, the single best partition may miss relevant information, and a consensus solution may blur complementary communities. Here we address this degeneracy problem with coarse-grained descriptions of the solution landscape. We cluster network partitions based on their similarity and suggest an approach to determine the minimum number of searches required to describe the solution landscape adequately. To make good use of all partitions, we also propose different ways to explore the solution landscape, including a significance clustering procedure. We test these approaches on synthetic networks and a real-world network using two contrasting community-detection algorithms: The algorithm that can identify more general structures requires more searches, and networks with clearer community structures require fewer searches. We also find that exploring the coarse-grained solution landscape can reveal complementary solutions and enable more reliable community detection.
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| 2. |
- Calatayud, Joaquín, et al.
(författare)
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Positive associations among rare species and their persistence in ecological assemblages
- 2020
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Ingår i: Nature Ecology & Evolution. - : Nature Publishing Group. - 2397-334X. ; 4:1, s. 40-45
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Tidskriftsartikel (refereegranskat)abstract
- According to the competitive exclusion principle, species with low competitive abilities should be excluded by more efficient competitors; yet, they generally remain as rare species. Here, we describe the positive and negative spatial association networks of 326 disparate assemblages, showing a general organization pattern that simultaneously supports the primacy of competition and the persistence of rare species. Abundant species monopolize negative associations in about 90% of the assemblages. On the other hand, rare species are mostly involved in positive associations, forming small network modules. Simulations suggest that positive interactions among rare species and microhabitat preferences are the most probable mechanisms underpinning this pattern and rare species persistence. The consistent results across taxa and geography suggest a general explanation for the maintenance of biodiversity in competitive environments. Analysing spatial association networks among >300 terrestrial and aquatic assemblages, the authors find that the majority of negative associations involve abundant species. In contrast, rare species form mostly positive associations, potentially explaining their persistence in natural communities.
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| 3. |
- Calatayud, Joaquín, et al.
(författare)
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Regularities in species’ niches reveal the world’s climate regions
- 2021
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Ingår i: eLIFE. - : eLife Sciences Publications Ltd.. - 2050-084X. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- Climate regions form the basis of many ecological, evolutionary, and conservation studies. However, our understanding of climate regions is limited to how they shape vegetation: They do not account for the distribution of animals. Here we develop a network-based framework to identify important climates worldwide based on regularities in realized niches of about 26,000 tetrapods. We show that high-energy climates, including deserts, tropical savannas, and steppes, are consistent across animal-and plant-derived classifications, indicating similar underlying climatic determinants. Conversely, temperate climates differ across all groups, suggesting that these climates allow for idiosyncratic adaptations. Finally, we show how the integration of niche classifications with geographical information enables the detection of climatic transition zones and the signal of geographic and historical processes. Our results identify the climates shaping the distribution of tetrapods and call for caution when using general climate classifications to study the ecology, evolution, or conservation of specific taxa.
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| 4. |
- Edstrom, Per, et al.
(författare)
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Geometry Related Inter-Instrument Differences in Spectrophotometric Measurements
- 2010
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Ingår i: Nordic Pulp & Paper Research Journal. - : Walter de Gruyter GmbH. - 0283-2631 .- 2000-0669. ; 25:2, s. 221-232
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Tidskriftsartikel (refereegranskat)abstract
- The L&W Elrepho d/0 and the Spectrolino 45/0 instruments are examined using paper samples with different properties. External factors that influence the measurements such as the sample background, the instrument calibration and the sample inhomogeneity are studied, and a methodology for their minimization is presented. Experimental measurements show that such external factors, if not minimized by proper routines, affect the inter-instrument differences far more (up to 4-5 Delta E-ab(star)) than the instrument geometry (the effect of which is small and of order 0.1 Delta E-ab(star)). The DORT2002 radiative transfer model is used to simulate differences caused by instrument geometry. The simulated and measured differences are found to agree in magnitude, and the differences are mapped against sample properties. It is observed that the 45/0 instrument detects higher reflectance from paper samples with negligible absorption and transmittance. When there is considerable absorption (dyed samples) or transmittance (thin samples), the d/0 instrument detects higher reflectance. The physical mechanism behind this behavior is studied and explained using DORT2002, and the instrument differences are shown to depend on the anisotropy of the reflected light. The model/measurement agreement is satisfactory as the characteristic behavior is captured in almost all cases studied. This new understanding is important for facilitating accurate data exchange between the paper and graphic arts industries, but also for interpretation of reflectance measurements in general.
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| 5. |
- Edström, Per, et al.
(författare)
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Geometry Related Inter-Instrument Differences in Spectrophotometric Measurements
- 2010
-
Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 25:2, s. 221-232
-
Tidskriftsartikel (refereegranskat)abstract
- The L&W Elrepho d/0 and the Spectrolino 45/0 instruments are examined using paper samples with different properties. External factors that influence the measurements such as the sample background, the instrument calibration and the sample inhomogeneity are studied, and a methodology for their minimization is presented. Experimental measurements show that such external factors, if not minimized by proper routines, affect the inter-instrument differences far more (up to 4-5 Delta E-ab(star)) than the instrument geometry (the effect of which is small and of order 0.1 Delta E-ab(star)). The DORT2002 radiative transfer model is used to simulate differences caused by instrument geometry. The simulated and measured differences are found to agree in magnitude, and the differences are mapped against sample properties. It is observed that the 45/0 instrument detects higher reflectance from paper samples with negligible absorption and transmittance. When there is considerable absorption (dyed samples) or transmittance (thin samples), the d/0 instrument detects higher reflectance. The physical mechanism behind this behavior is studied and explained using DORT2002, and the instrument differences are shown to depend on the anisotropy of the reflected light. The model/measurement agreement is satisfactory as the characteristic behavior is captured in almost all cases studied. This new understanding is important for facilitating accurate data exchange between the paper and graphic arts industries, but also for interpretation of reflectance measurements in general.
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| 6. |
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| 7. |
- Edvardsson, Sverker, et al.
(författare)
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Solving equations through particle dynamics
- 2015
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Ingår i: Computer Physics Communications. - : Elsevier. - 0010-4655 .- 1879-2944. ; 197, s. 169-181
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Tidskriftsartikel (refereegranskat)abstract
- The present work evaluates a recently developed particle method (DFPM). The basic idea behind this method is to utilize a Newtonian system of interacting particles that through dissipation solves mathematical problems. We find that this second order dynamical system results in an algorithm that is among the best methods known. The present work studies large systems of linear equations. Of special interest is the wide eigenvalue spectrum. This case is common as the discretization of the continuous problem becomes dense. The convergence rate of DFPM is shown to be in parity with that of the conjugate gradient method, both analytically and through numerical examples. However, an advantage with DFPM is that it is cheaper per iteration. Another advantage is that it is not restricted to symmetric matrices only, as is the case for the conjugate gradient method. The convergence properties of DFPM are shown to be superior to the closely related approach utilizing only a first order dynamical system, and also to several other iterative methods in numerical linear algebra. The performance properties are understood and optimized by taking advantage of critically damped oscillators in classical mechanics. Just as in the case of the conjugate gradient method, a limitation is that all eigenvalues (spring constants) are required to be of the same sign. DFPM has no other limitation such as matrix structure or a spectral radius as is common among iterative methods. Examples are provided to test the particle algorithm’s merits and also various performance comparisons with existent numerical algorithms are provided.
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| 8. |
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| 9. |
- Gustafsson Coppel, Ludovic, 1973-, et al.
(författare)
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Angular dependence of fluorescence from turbid media
- 2015
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Ingår i: Optics Express. - : Optical Society of America. - 1094-4087. ; 23:15, s. 19552-19564
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Tidskriftsartikel (refereegranskat)abstract
- We perform Monte Carlo light scattering simulations to study the angular distribution of the fluorescence emission from turbid media and compare the results to measured angular distributions from fluorescing white paper samples. The angular distribution of fluorescence emission is significantly depending on the concentration of fluorophores. The simulations show also a dependence on the angle of incidence that is however not as evident in the measurements. A detailed analysis of the factors affecting this angular distribution indicates that it is strongly correlated to the mean depth of the fluorescence process. The findings can find applications in fluorescence spectroscopy and are of particular interest when optimizing the impact of fluorescence on e.g.the appearance of paper as the measured values are angle dependent.
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| 10. |
- Gustafsson Coppel, Ludovic, 1975-, et al.
(författare)
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Extension of the Stokes equation for layered constructions to fluorescent turbid media
- 2012
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Ingår i: Journal of the Optical Society of America A. - : Optical Society of America. - 1084-7529 .- 1520-8532. ; 29:4, s. 574-578
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Tidskriftsartikel (refereegranskat)abstract
- Expressions relating the bispectral reflectance of a stack of n fluorescinglayers to each individual layer's reflectance and transmittance arederived. This theoretical framework is used together with recentlyproposed extensions of the Kubelka--Munk model to study the fluorescencefrom layered turbid media. For one layer over a reflecting background,the model is shown to give the same results as a previous model.The extension to n layers with different optical properties allowssimulating the bispectral reflectance from a pad of layered turbidmedia. The applicability of the model is exemplified with an optimizationof fluorophore distribution in layered turbid media.
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| 11. |
- Gustafsson Coppel, Ludovic, 1975-, et al.
(författare)
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Fluorescence model for multi-layer papers using conventional spectrophotometers
- 2012
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Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 27:2, s. 418-425
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Tidskriftsartikel (refereegranskat)abstract
- We present an extension of a Kubelka- Munk based fluorescence model in which we introduce an apparent scattering (S UV) and absorption (K UV) coefficient for all wavelengths below 400 nm. We describe a method for modelling the total radiance factor of multi-layer papers and for estimating the optical parameters (S, K and Q) of each layer. Assuming that the fluorescent whitening agent only absorbs below 400 nm, we are able to determine S UV, K UV and the apparent quantum efficiency, Q(UV,λ) for 400 nm<λ<700 nm, from spectral radiance measurements in the visual part of the electromagnetic spectrum. We test the proposed method on different layered constructions made of three individual pilot paper layers. The proposed method allows the papermaker to determine the illumination independent fluorescence characteristics of single- and multilayer paper layers using a conventional singlemonochromator spectrophotometer operating in the visible part of the electromagnetic spectrum, and also to predict the radiance factor of fluorescing layered papers.
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| 12. |
- Gustafsson Coppel, Ludovic, 1975-, et al.
(författare)
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Lateral light scattering in paper - MTF simulation and measurement
- 2011
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Ingår i: Optics Express. - : Optical Society of America. - 1094-4087. ; 19:25, s. 25181-25187
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Tidskriftsartikel (refereegranskat)abstract
- The modulation transfer function (MTF) of 22 paper samples is computed using Monte Carlo simulations with isotropic or strongly forward single scattering. The inverse frequency at half maximum of the MTF (kp) is found inappropriate as a single metric for the MTF since it is insensitive to the shape of the modeled and simulated MTF. The single scattering phase function has a significant impact on the shape of the MTF, leading to more lateral scattering. However, anisotropic single scattering cannot explain the larger lateral scattering observed in paper. It is argued that the directional inhomogeneity of paper requires a light scattering model with both the phase function and scattering distances being dependent on the absolute direction.
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| 13. |
- Hägglund, Håkan, et al.
(författare)
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Dependence between paper properties and spectral optical response of uncoated paper
- 2012
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Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 27:2, s. 440-444
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a method to describe, with good accuracy, the relation between variations in paper properties and variations of the spectral optical response of an uncoated paper. The dependence between density, filler content, grammage, and the spectral optical response is characterized by a multivariate model. The model is based on large-scale measurements data on a set of paper samples that have been produced with different values of grammage, density and filler content, representing the variations within a normal 80 g/m2 uncoated paper. From the optical measurements the light scattering (s) and light absorption (k) coefficients have been estimated according to the Kubelka-Munk theory.The results from this study will give valuable input to optical modeling activities, where the optical variations are predicted from measured small-scale variations in underlying paper properties.The variations in the paper properties can be used to model the light scattering coefficient, s, but there were too small variations in the light absorption coefficient, k, to find any significant dependence to the paper properties for the samples studied in this work. Furthermore, linear models give sufficient accuracy in the intervals studied. Additional findings from this study are the different effects of wet-pressing and calendering on the light scattering coefficient.
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| 14. |
- Johansson, Niklas, et al.
(författare)
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Influence of finite-sized detection solid angle on bidirectional reflectance distribution function measurements
- 2014
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Ingår i: Applied Optics. - : Optical Society of America. - 1559-128X .- 2155-3165. ; 53:6, s. 1212-1220
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Tidskriftsartikel (refereegranskat)abstract
- This paper deals with limitations and often overlooked sources of error introduced in compact double-beam goniophotometers. It is shown that relative errors in measured radiance factor, comparable to the total measurement uncertainty, can be introduced if recommended corrections are not carried out. Two different error sources are investigated, both related to the size of the detection solid angle. The first is a geometrical error that occurs when the size of the illuminated area and detector aperture are comparable to the distance between them. The second is a convolution error due to variations in radiant flux over the detector aperture, which is quantified by simulating the full 3D bidirectional reflectance distribution function (BRDF) of a set of samples with different degrees of anisotropic reflectance. The evaluation is performed for a compact double-beam goniophotometer using different detection solid angles, and it is shown that both error sources introduce relative errors of 1%–3%, depending on viewing angle and optical properties of the sample. Commercially available compact goniophotometers, capable of absolute measurements, are becoming more and more common, and the findings in this paper are therefore important for anyone using or planning to use this type of instrument.
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| 15. |
- Johansson, Niklas, 1973-
(författare)
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Measuring and modelling light scattering in paper
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Avhandlingen behandlar de teoretiska och praktiska aspekterna av att använda spektrala vinkelupplösta reflektansmätningar för optisk karakterisering av fiberbaserade material såsom papper och kartong. En spektral goniofotometer används för att mäta det reflekterade ljusets vinkelfördelning. En stor del av arbetet utgörs av att utvärdera instrumentets noggrannhet, samt utreda hur de vinkelupplösta mätningarna skall utföras på bästa sätt för att erhålla en så fullständig karakterisering som möjligt. Det reflekterade ljuset består av tre komponenter; ytreflektans, bulkreflektans samt fluorescens. En fullständig karakterisering förutsätter att dessa tre komponenter kan analyseras separat, vilket i detta arbete görs genom nyutvecklade metoder.En metod har utvecklats för separation av ytreflektans och bulkreflektans. Metoden bygger på att analysera hur den totala reflektansen förändras vid ökande absorption i det reflekterande materialet. Absorptionen kontrolleras genom inkjet-tryckning där tryckfärg appliceras på substratet i sådan mängd att bulkreflektansen helt släcks ut. Genom att kombinera mätningar på tryckt och otryckt substrat kan de båda komponenterna separeras. Trots att ytreflektansen från ett matt papper är liten i förhållande till bulkreflektansen, så visar resultaten att den ökar markant med ökande betraktningsvinkel och kan därmed ha stor inverkan på den totala reflektansen. Bidraget från fluorescens kan kvantitativt analyseras genom att kombinera mätningar utförda med respektive utan UV-filter. Vinkelupplösta mätningar och Monte Carlo-simuleringar av fluorescensens vinkelfördelning visar att dess anisotropi är relaterad till det medeldjup vid vilket fluorescensen emitteras. Resultaten förklarar observerade skillnader och motstridigheter i tidigare rapporterade studier kring huruvida fluorescens kan anses vara Lamberskt fördelad.Samtliga goniofotometriska mätningar är utförda med ett kompakt, kommersiellt tillgängligt, dubbelstråleinstrument. För att undersöka instrumentets lämplighet för absoluta reflektansmätningar utförs en analys av dess mätnoggrannhet. Resultaten visar att instrumentets kompakta storlek i kombination med den anisotropa reflektansen från papper introducerar systematiska fel av samma storleksordning som den totala mätnoggrannheten. Dessa fel uppstår på grund av den relativt stora detektorapertur som måste användas vid mätningar av diffus reflektans, vilket är karakteristiskt för papper och kartong. Resultaten visar även att felen är störst vid flacka mätvinklar och för prover med hög grad av anisotropisk reflektans, och en geometrisk korrektionsmetod för denna typ av systematiska fel föreslås.Spektrala och vinkelupplösta mätningar medför per automatik stora mängder mätdata. Genom att använda strålningstransportteori som en matematisk modell för hur ljus sprids i papper kan mätdatat reduceras till en uppsättning beskrivande materialparameterar. Att uppskatta dessa optiska parametrar utifrån vinkelupplösta reflektansmätningar är i sig ett komplicerat problem, vilket dessutom är känsligt för mätfel och val av mätvinklar. Detta inversa problem analyseras i detalj, och speciellt hur valet av mätvinklar kan reduceras utan att försämra förutsättningarna för estimeringen. Simuleringar visar att mätningarna kan begränsas till infallsplanet, eller till och med enbart framåtriktningen, så länge tillräckligt flacka mätvinklar är inkluderade i mätsekvensen.
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| 16. |
- Johansson, Niklas, 1973-, et al.
(författare)
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Separation of surface and bulk reflectance by absorption of bulk scattered light
- 2013
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Ingår i: Applied Optics. - : Optical Society of America. - 1559-128X .- 2155-3165. ; 52:19, s. 4749-4754
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Tidskriftsartikel (refereegranskat)abstract
- A method is proposed for separating light reflected from turbid media with a rough surface into a bulkand a surface component. Dye is added to the sample, thereby increasing absorption and canceling bulkscattering. The remaining reflected light is surface reflectance, which can be subtracted from the totalreflectance of an undyed sample to obtain the bulk component. The method is applied to paper wherethe addition of dye is accomplished by inkjet printing. The results show that the bulk scattered light isefficiently canceled, and that both the spectrally neutral surface reflectance and the surface topographyof the undyed paper is maintained. The proposed method is particularly suitable for characterization ofdielectric, highly randomized materials with significant bulk reflectance and rough surfaces, which aredifficult to analyze with existing methods. A reliable separation method opens up for new ways of analyzing,e.g., biological tissues and optical coatings, and is also a valuable tool in the development of morecomprehensive reflectance models.
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| 17. |
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| 18. |
- Karlsohn, Thomas, 1967-, et al.
(författare)
-
Ta inte ifrån oss makten över tanken
- 2019
-
Ingår i: Upsala. - Uppsala. - 1104-0173. ; :15 okt
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 19. |
- Linder, Tomas, et al.
(författare)
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Lateral light scattering in fibrous media
- 2013
-
Ingår i: Optics Express. - 1094-4087. ; 21:6, s. 7835-7840
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Tidskriftsartikel (refereegranskat)abstract
- Lateral light scattering in fibrous media is investigated by computing the modulation transfer function (MTF) of 22 paper samples using a Monte Carlo model. The simulation tool uses phase functions from infinitely long homogenous cylinders and the directional inhomogeneity of paper is achieved by aligning the cylinders in the plane. The inverse frequency at half maximum of the MTF is compared to both measurements and previous simulations with isotropic and strongly forward single scattering phase functions. It is found that the conical scattering by cylinders enhances the lateral scattering and therefore predicts a larger extent of lateral light scattering than models using rotationally invariant single scattering phase functions. However, it does not fully reach the levels of lateral scattering observed in measurements. It is argued that the hollow lumen of a wood fiber or dependent scattering effects must be considered for a complete description of lateral light scattering in paper.
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| 20. |
- Namedanian, Mahziar, et al.
(författare)
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Analysis of Optical and Physical Dot Gain by Microscale Image Histogram and Modulation Transfer Functions
- 2013
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Ingår i: Journal of Imaging Science and Technology. - 1062-3701 .- 1943-3522. ; 57:2, s. 020504-1-020504-5
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Tidskriftsartikel (refereegranskat)abstract
- The color of a print is affected by ink spreading and lateral light scattering in the substrate, making printed dots appear larger. Characterization of physical and optical dot gain is crucial for the graphic arts and paper industries. We propose a novel approach to separate physical from optical dot gain by use of a high-resolution camera. This approach is based on the histogram of microscale images captured by the camera. Having determined the actual physical dot shape, we estimate the modulation transfer function (MTF) of the paper substrate. The proposed method is validated by comparing the estimated MTF of 11 offset printed coated papers to the MTF obtained from the unprinted papers using measured and Monte Carlo simulated edge responses.
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| 21. |
- Neuman, Magnus, 1979-, et al.
(författare)
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A partial explanation of the dependence between light scattering and light absorption in the Kubelka-Munk model
- 2012
-
Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 27:2, s. 426-430
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Tidskriftsartikel (refereegranskat)abstract
- The Kubelka-Munk scattering and absorption coefficients of a set of paper samples are assessed using reflectance measurements in d/0 geometry. The coefficients display the widely studied dependence between light scattering and light absorption, since the light scattering coefficient decreases in regions of high absorption. It is shown using general radiative transfer theory that part of this dependence can be explained and eliminated by taking into account the geometry of the d/0 instrument and the single scattering anisotropy, thus capturing the angular variations of the light reflected from the samples. These findings allow the papermaker to better predict the reflectance from mixtures of pulps, fillers, dye, and FWA, and to better evaluate bleaching efforts.
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| 22. |
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| 23. |
- Neuman, Magnus, et al.
(författare)
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Angle resolved color of bulk scattering media
- 2011
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Ingår i: Applied Optics. - 1559-128X .- 2155-3165. ; 50:36, s. 6555-6563
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Tidskriftsartikel (refereegranskat)abstract
- The angle resolved reflectance factor of matte samples is measured with a goniophotometer and simulated using radiative transfer theory. Both measurements and simulations display the same characteristic dependence of the reflectance factor on the observation angle. The angle resolved reflectance spectra are translated to CIELAB color coordinates and the angular color differences are found to be surprisingly large. A chromatic adaptation that is dependent on the observation angle is suggested, in which a nonabsorbing opaque medium is used as the reference white, and the angular color differences are then reduced. Furthermore, the use of an undyed paper as the reference white is evaluated. The angular lightness differences are then reduced further, but the angular differences in chroma are still large. It is suggested that smaller variations in perceived color could be explained by angle dependent chromatic adaptation and a limited sensitivity of the human visual system to changes in chroma.
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| 24. |
- Neuman, Magnus
(författare)
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Angle Resolved Light Scattering in Turbid Media : Analysis and Applications
- 2011
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Light scattering in turbid media is essential for such diverse application areas as paper and print, computer rendering, optical tomography, astrophysics and remote sensing. This thesis investigates angular variations of light reflected from plane-parallel turbid media using both mathematical models and reflectance measurements, and deals with several applications. The model of most widespread use in industry is the Kubelka-Munk model, which neglects angular variations in the reflected light. This thesis employs a numerical solution of the angle resolved radiative transfer problem to better understand how the angular variations are related to medium properties. It is found that the light is reflected anisotropically from all media encountered in practice, and that the angular variations depend on the medium absorption and transmittance and on the angular distribution of the incident light. If near-surface bulk scattering dominates, as in strongly absorbing or highly transmitting media or obliquely illuminated media, relatively more light is reflected in large polar (grazing) angles. These results are confirmed by measurements using a set of paper samples. The only situation with isotropic reflectance is when a non-transmitting, non-absorbing medium is illuminated diffusely. This is the only situation where the Kubelka-Munk model is exactly valid. The results also show that there is no such thing as an ideal bulk scattering diffusor, and these findings can affect calibration and measurement procedures defined in international standards.The implications of the presented results are studied for a set of applications including reflectance measurements, angle resolved color and point spreading. It is seen that differences in instrument detection and illumination geometry can result in measurement differences. The differences are small and if other sources of error - such as fluorescence and gloss - are not eliminated, the differences related to instrument geometry become difficult to discern. Furthermore, the angle resolved color of a set of paper samples is assessed both theoretically and experimentally. The chroma decreases and the lightness increases as the observation polar angle increases. The observed differences are clearly large, and it is an open issue how angle resolved color should be handled. Finally, the dependence of point spreading in turbid media on the medium parameters is studied. The asymmetry factor is varied while maintaining constant the optical response in a standardized measurement geometry. It is seen that the point spreading increases as forward scattering becomes more dominant, and that the effect is larger if the medium is low-absorbing with large mean free path. A generic model of point spreading must therefore capture the dependence on all of these medium parameters.This thesis shows that turbid media reflect light anisotropically, and angle resolved radiative transfer models are therefore necessary to capture this. Using simplified models can introduce errors in an uncontrolled manner. The results presented potentially have consequences for all applications dealing with light scattering, some of which are studied here.
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| 25. |
- Neuman, Magnus, et al.
(författare)
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Angular Variations of Color in Turbid Media – the Influence of Bulk Scattering on Goniochromism in Paper
- 2010
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Ingår i: 5th European Conference on Colour in Graphics, Imaging, and Vision and 12th International Symposium on Multispectral Colour Science 2010, CGIV 2010/MCS'10. - 9781617388897 ; , s. 407-413
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Konferensbidrag (refereegranskat)abstract
- The angular variations of color of a set of paper samples are experimentally assessed using goniophotometric measurements. The corresponding simulations are done using a radiative transfer based simulation tool, thus considering only the contribution of bulk scattering to the reflectance. It is seen that measurements and simulations agree and display the same characteristics, with the lightness increasing and the chroma decreasing as the observation polar angle increases. The decrease in chroma is larger the more dye the paper contains. Based on previous results about anisotropic reflectance from turbid media these findings are explained. The relative reflectance in large polar angles of wavelengths with strong absorption is higher than that of wavelengths with low absorption. This leads to a loss of chroma and color information in these angles. The increase in lightness is a result of the anisotropy affecting all wavelengths equally, which is the case for transmitting media and obliquely incident illumination. The only case with no color variations of this kind is when a nonabsorbing, non-transmitting medium is illuminated diffusely. The measured and simulated color differences are clearly large, and it is an open issue how angle resolved color should be handled in standard color calculations.
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| 26. |
- Neuman, Magnus
(författare)
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Anisotropic reflectance from paper : measurements, simulations and analysis
- 2006
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Arbetet innehåller en grundläggande teoretisk och experimentell undersökning av anisotrop (icke-diffus) reflektans från papper. Fenomenet kopplas till papperets ljusabsorptionsgrad, fenomenets effekt på standardiserade reflektansmätningar utreds, och orsaker till fenomenet redovisas.
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| 27. |
- Neuman, Magnus, 1979-, et al.
(författare)
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Anisotropic reflectance from turbid media. I. Theory
- 2010
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Ingår i: Journal of the Optical Society of America A. - 0740-3232. ; 27:5, s. 1032-1039
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Tidskriftsartikel (refereegranskat)abstract
- It is shown that the intensity of light reflected from plane-parallel turbid media is anisotropic in all situations encountered in practice. The anisotropy, in the form of higher intensity in large polar angles, increases when the amount of near-surface bulk scattering is increased, which dominates in optically thin and highly absorbing media. The only situation with isotropic intensity is when a non-absorbing infinitely thick medium is illuminated diffusely. This is the only case where the Kubelka-Munk model gives exact results and there exists an exact translation between Kubelka-Munk and general radiative transfer. This also means that a bulk scattering perfect diffusor does not exist. Angular resolved models are thus crucial for a correct understanding of light scattering in turbid media. The results are derived using simulations and analytical calculations. It is also shown that there exists an optimal angle for directional detection which minimizes the error introduced when using the Kubelka-Munk model to interpret reflectance measurements with diffuse illumination.
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| 28. |
- Neuman, Magnus, 1979-, et al.
(författare)
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Anisotropic reflectance from turbid media. II. Measurements
- 2010
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Ingår i: Journal of the Optical Society of America A. - : The Optical Society. - 0740-3232 .- 1084-7529 .- 1520-8532. ; 27:5, s. 1040-1045
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Tidskriftsartikel (refereegranskat)abstract
- The anisotropic reflectance from turbid media predicted using the radiative transfer based DORT2002 model is experimentally verified through goniophotometric measurements. A set of paper samples with varying amount of dye and thickness is prepared and their angle resolved reflectance is measured. An alleged perfect diffusor is also included. The corresponding simulations are performed. A complete agreement between the measurements and model predictions is seen regarding the characteristics of the anisotropy. They show that relatively more light is reflected in large polar angles when the absorption or illumination angle is increased or when the medium thickness is decreased. This is due to the relative amount of near-surface bulk scattering increasing in these cases. This affects the application of the Kubelka-Munk model as well as standards for reflectance measurements and calibration routines.
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| 29. |
- Neuman, Magnus
(författare)
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Applied problems and computational methods in radiative transfer
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Light scattering in turbid media is essential for such diverse applications as paperand print, computer rendering, optical tomography, astrophysics and remote sensing.This thesis investigates angular variations of light reflected from plane-parallelturbid media using both mathematical models and reflectance measurements, dealswith several applications and proposes novel computational methods for solving thegoverning equations.Angular variations of light reflected from plane-parallel turbid media is studiedusing both mathematical models and reflectance measurements. It is found that thelight is reflected anisotropically from all media encountered in practice, and that theangular variations depend on the medium absorption and transmittance and on theangular distribution of the incident light. If near-surface bulk scattering dominates,as in strongly absorbing or highly transmitting media or obliquely illuminated media,relatively more light is reflected in large polar (grazing) angles. These results areconfirmed by measurements using a set of paper samples. The only situation withisotropic reflectance is when a non-transmitting, non-absorbing medium is illuminateddiffusely, and it is shown that this is the only situation where the widely usedKubelka-Munk model is exactly valid.A number of applied problems is studied, including reflectance measurements,angle resolved color and point spreading. It is seen that differences in instrumentdetection and illumination geometry can result in measurement differences. The differencesare small and if other sources of error — such as fluorescence and gloss— are not eliminated, the differences related to instrument geometry become difficultto discern. Furthermore, the dependence of point spreading in turbid mediaon the medium parameters is studied. The asymmetry factor is varied while maintainingconstant the optical response in a standardized measurement geometry. It isseen that the point spreading increases as forward scattering becomes more dominant,and that the effect is larger if the medium is low-absorbing with large meanfree path. It is argued that the directional inhomogeneity of the scattering mediummust be captured by the model to reproduce experimental results. Finally, the angleresolved color of a set of paper samples is assessed both theoretically and experimentally.The chroma decreases and the lightness increases as the observation polarangle increases. The observed differences are clearly large, and a modification ofthe L∗a∗b∗ formalism including angle dependent chromatic adaptation is suggestedhere to handle this situation.The long standing issue of parameter dependence in the Kubelka-Munk modelis partially explained by recognizing that light reflected from paper samples in standardizedmeasurements has angular variations, and by using the appropriatemodelin the calculation of the scattering and absorption coefficients.The radiative transfer (RT) equation is solved with a recently proposed particlemethod (DFPM), both in standard cases and in cases previously considered intractable.Fluorescence is added to the RT equation, thus including wavelength asan additional dimension, and this equation is solved using DFPM. The discrete RTequation can be written as a system of linear equations, and a comprehensive analysisof the convergence properties of DFPM when solving this type of problems ispresented.
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| 30. |
- Neuman, Magnus, et al.
(författare)
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Cross-validation of correlation networks using modular structure
- 2022
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Ingår i: Applied Network Science (ANS). - : Springer Science and Business Media LLC. - 2364-8228. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- Correlation networks derived from multivariate data appear in many applications across the sciences. These networks are usually dense and require sparsification to detect meaningful structure. However, current methods for sparsifying correlation networks struggle with balancing overfitting and underfitting. We propose a module-based cross-validation procedure to threshold these networks, making modular structure an integral part of the thresholding. We illustrate our approach using synthetic and real data and find that its ability to recover a planted partition has a step-like dependence on the number of data samples. The reward for sampling more varies non-linearly with the number of samples, with minimal gains after a critical point. A comparison with the well-established WGCNA method shows that our approach allows for revealing more modular structure in the data used here.
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| 31. |
- Neuman, Magnus, et al.
(författare)
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Modelling and Control of Series HEVs Including Resistive Losses and Varying Engine Efficiency
- 2009
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Ingår i: Proceedings of SAE 2009 World Congress. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International.
-
Konferensbidrag (refereegranskat)abstract
- A model of a series HEV (Hybrid Electric Vehicle) including resistive losses in the energy storage and varying engine and generator efficiency is presented. The purpose is to study how system properties affect the optimal control of series HEVs. We show that there is an inherent trade-off in the control of such a system, based on the characteristics of the efficiency curve of the EGU (Engine and Generator Unit) together with the energy storage internal resistance, capacitance and energy level. The relation between these properties determines the optimal control of the EGU, and this is thus the mechanism behind all optimal control problems using a similar model setup. We illustrate our reasoning using deterministic dynamic programming where system properties are varied and the optimal control is studied.
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| 32. |
- Neuman, Magnus, et al.
(författare)
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Module-based regularization improves Gaussian graphical models when observing noisy data
- 2024
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Ingår i: APPLIED NETWORK SCIENCE. - : Springer Nature. - 2364-8228. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Inferring relations from correlational data allows researchers across the sciences to uncover complex connections between variables for insights into the underlying mechanisms. The researchers often represent inferred relations using Gaussian graphical models, requiring regularization to sparsify the models. Acknowledging that the modular structure of these inferred networks is often studied, we suggest module-based regularization to balance under- and overfitting. Compared with the graphical lasso, a standard approach using the Gaussian log-likelihood for estimating the regularization strength, this approach better recovers and infers modular structure in noisy synthetic and real data. The module-based regularization technique improves the usefulness of Gaussian graphical models in the many applications where they are employed.
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| 33. |
- Neuman, Magnus
(författare)
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PISA data clusters reveal student and school inequality that affects results
- 2022
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 17:5
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Tidskriftsartikel (refereegranskat)abstract
- The data from the PISA survey show that student performance correlates with socio-economic background, that private schools have higher results and more privileged students, and that this varies between countries. We explore this further and analyze the PISA data using methods from network theory and find clusters of countries whose students have similar performance and socio-economic background. Interestingly, we find a cluster of countries, including China, Spain and Portugal, characterized by less privileged students performing well. When considering private schools only, some countries, such as Portugal and Brazil, are in a cluster with mostly wealthy countries characterized by privileged students. Swedish grades are compared to PISA results, and we see that the higher grades in private schools are in line with the PISA results, suggesting that there is no grade inflation in this case, but differences in socio-economic background suggest that this is due to school segregation.
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| 34. |
- Neuman, Magnus, et al.
(författare)
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Point spreading in turbid media with anisotropic single scattering
- 2011
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Ingår i: Optics Express. - : OSA. - 1094-4087. ; 19:3, s. 1915-1920
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Tidskriftsartikel (refereegranskat)abstract
- Point spreading is investigated using general radiative transfer theory. We find that the single scattering anisotropy plays a significant role for point spreading together with the medium mean free path, single scattering albedo and thickness. When forward scattering dominates, the light will on average undergo more scattering events to give a specific optical response in reflectance measurements. This will significantly increase point spreading if the medium is low absorbing with large mean free path. Any fundamental and generic model of point spreading must capture the dependence on all of these medium characteristics.
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| 35. |
- Neuman, Magnus, et al.
(författare)
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Rule-Based Control of Series HEVs Derived from Deterministic Dynamic Programming
- 2008
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Rapport (refereegranskat)abstract
- We present a model of a series HEV including resistive losses in the energy storage and varying efficiency of the combustion engine and generator. An optimal control problem minimizing fuel consumption is solved using the model and deterministic dynamic programming. It is evaluated on several standard city bus driving cycles and the solutions are analyzed to extract rules useful for real-time controlling. The resulting real-time strategy is compared to the optimal control using simulations. The strategy has a threshold value determining when to switch off the generator. This threshold value has a driving cycle dependent optimum giving the minimum increase in fuel consumption compared to the optimal control, and the optimal value can thus be chosen based on driving cycle characteristics. We see that the optimal value is related to the mean power demand of the driving cycle. The proposed real-time strategy performs well, and a minimum increase of 5 % can be achieved even on a driving cycle not used for rule extraction.
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| 36. |
- Neuman, Magnus, et al.
(författare)
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Solving the radiative transfer equation with a mathematical particle method
- 2015
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Ingår i: Optics Letters. - : Optics Info Base, Optical Society of America. - 0146-9592 .- 1539-4794. ; 40:18, s. 4325-4328
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Tidskriftsartikel (refereegranskat)abstract
- We solve the radiative transfer equation (RTE) using a recently proposed mathematical particle method, originally developed for solving general functional equations. We show that, in the case of the RTE, it gives several advantages, such as handling arbitrary boundary conditions and phase functions and avoiding numerical instability in strongly forward-scattering media. We also solve the RTE, including fluorescence, and an example is shown with a fluorescence cascade where light is absorbed and emitted in several steps. We show that the evaluated particle method is straightforward to implement, which is in contrast with many traditional RTE solvers, but a potential drawback is the tuning of the method parameters.
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| 37. |
- Neuman, Åsa, et al.
(författare)
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Infant wheeze, comorbidities and school age asthma
- 2014
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Ingår i: Pediatric Allergy and Immunology. - : Wiley. - 0905-6157 .- 1399-3038. ; 25:4, s. 380-386
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Tidskriftsartikel (refereegranskat)abstract
- Background: Factors associated with early onset of wheeze have been described, but there is limited knowledge on which of these infant wheezers who will have developed asthma in school age. The aim was to identify clinical risk factors for asthma in the 8-yr-old children that wheezed during infancy in a population-based setting. Methods: Three thousand two hundred and fifty-one children from a population-based birth cohort followed prospectively from infancy until age 8 yr were included in the study. Data were analyzed using multivariate logistic regression analysis. Results: Parents reported any wheeze episode before age 2 yr in 823 subjects (25%). Infant wheezers had an almost fourfold risk of asthma at age 8 [adjusted odds ratio (aOR) 3.68, 95% CI 2.74-4.96], equivalent to an asthma prevalence of 14% compared with 4% among non-wheezers (p < 0.001). After adjustments for sex, exposure to tobacco smoke and indoor dampness/mould, allergic heredity (aOR 1.53, 95% CI 1.02-2.30), increased frequency of wheeze (aOR 3.41, 95% CI 2.09-5.56 for children with >= 3 episodes compared with <= 2 episodes during the first 2 yr of life), infant eczema (aOR 2.31, 95% CI 1.52-3.49), and recurrent abdominal pain (aOR 2.33, 95% CI 1.30-4.16) remained risk factors for school age asthma in the infant wheezing group. Conclusions: Among infant wheezers, allergic heredity, increased severity of wheeze, infant eczema, and recurrent abdominal pain were independent risk factors for asthma at age 8 yr. Among children with three or four of these risk factors, 38% had asthma at school age.
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| 38. |
- Neuman, Åsa, et al.
(författare)
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Maternal Smoking in Pregnancy and Asthma in Preschool Children A Pooled Analysis of Eight Birth Cohorts
- 2012
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Ingår i: American Journal of Respiratory and Critical Care Medicine. - 1073-449X .- 1535-4970. ; 186:10, s. 1037-1043
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Tidskriftsartikel (refereegranskat)abstract
- Rationale: Although epidemiological studies suggest that exposure to maternal smoking during fetal and early life increases the risk of childhood wheezing and asthma, previous studies were not able to differentiate the effects of prenatal from postnatal exposure. Objectives: To assess the effect of exposure to maternal smoking only during pregnancy on wheeze and asthma among preschool-age children. Methods: A pooled analysis was performed based on individual participant data from eight European birth cohorts. Cohort-specific effects of maternal smoking during pregnancy, but not during the first year, on wheeze and asthma at 4 to 6 years of age were estimated using logistic regression and then combined using a random effects model. Adjustments were made for sex, parental education, parental asthma, birth weight, and siblings. Measurements and Main Results: Among the 21,600 children included in the analysis, 735 children (3.4%) were exposed to maternal smoking exclusively during pregnancy but not in the first year after birth. In the pooled analysis, maternal smoking only during pregnancy was associated with wheeze and asthma at 4 to 6 years of age, with adjusted odds ratios of 1.39 (95% confidence interval, 1.08-1.77) and 1.65 (95% confidence interval, 1.18-2.31), respectively. The likelihood to develop wheeze and asthma increased statistically significantly in a linear dose-dependent manner in relation to maternal daily cigarette consumption during the first trimester of pregnancy. Conclusions: Maternal smoking during pregnancy appears to increase the risk of wheeze and asthma among children who are not exposed to maternal smoking after birth.
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| 39. |
- Olen, O., et al.
(författare)
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Allergy-related diseases and recurrent abdominal pain during childhood - a birth cohort study
- 2014
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Ingår i: Alimentary Pharmacology & Therapeutics. - : Wiley. - 0269-2813 .- 1365-2036. ; 40:11, s. 1349-1358
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundAllergy and immune dysregulation may have a role in the pathophysiology of recurrent abdominal pain of functional origin, but previous studies of allergy-related diseases and abdominal pain have contradictory results. AimTo examine the association between allergy-related diseases or sensitisation during childhood and abdominal pain at age 12years. MethodsIn this birth cohort study of 4089 children, parents answered questionnaires regarding asthma, allergic rhinitis, eczema and food hypersensitivity (allergy-related diseases') at ages 0,1,2,4,8 and 12years. Blood for analyses of allergen-specific IgE was sampled at 4 and 8years. At 12years, the children answered questions regarding abdominal pain. Children with coeliac disease or inflammatory bowel disease were excluded. Associations were examined using multivariable logistic regression. ResultsAmong 2610 children with complete follow-up, 9% (n=237) reported abdominal pain at 12years. All allergy-related diseases were associated with concurrent abdominal pain at 12years and the risk increased with increasing number of allergy-related diseases (P for trend <0.001). Asthma at 1 and 2years and food hypersensitivity at 8years were significantly associated with abdominal pain at 12years. There was an increased risk of abdominal pain at 12years in children sensitised to food allergens at 4 or 8years, but in stratified analyses, this was confined to children whose parents had not reported food hypersensitivity at time of sensitisation. ConclusionAllergy-related diseases as well as sensitisation to food allergens were associated with an elevated risk of abdominal pain, and the risk increased with the number of allergy-related diseases.
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| 40. |
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| 41. |
- Rojas, Alexis, et al.
(författare)
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A multiscale view of the Phanerozoic fossil record reveals the three major biotic transitions
- 2021
-
Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 4:1
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Tidskriftsartikel (refereegranskat)abstract
- The hypothesis of the Great Evolutionary Faunas is a foundational concept of macroevolutionary research postulating that three global mega-assemblages have dominated Phanerozoic oceans following abrupt biotic transitions. Empirical estimates of this large-scale pattern depend on several methodological decisions and are based on approaches unable to capture multiscale dynamics of the underlying Earth-Life System. Combining a multilayer network representation of fossil data with a multilevel clustering that eliminates the subjectivity inherent to distance-based approaches, we demonstrate that Phanerozoic oceans sequentially harbored four global benthic mega-assemblages. Shifts in dominance patterns among these global marine mega-assemblages were abrupt (end-Cambrian 494 Ma; end-Permian 252 Ma) or protracted (mid-Cretaceous 129 Ma), and represent the three major biotic transitions in Earth's history. Our findings suggest that gradual ecological changes associated with the Mesozoic Marine Revolution triggered a protracted biotic transition comparable in magnitude to the end-Permian transition initiated by the most severe biotic crisis of the past 500 million years. Overall, our study supports the notion that both long-term ecological changes and major geological events have played crucial roles in shaping the mega-assemblages that dominated Phanerozoic oceans.
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| 42. |
- Thacher, Jesse D, et al.
(författare)
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Parental smoking and development of allergic sensitization from birth to adolescence
- 2016
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Ingår i: Allergy. European Journal of Allergy and Clinical Immunology. - : Wiley. - 0105-4538 .- 1398-9995. ; 71:2, s. 239-248
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The relation between secondhand tobacco smoke (SHS) exposure and the development of allergic sensitization in children is unclear. The aim of this study was to determine whether maternal smoking during pregnancy and postnatal SHS exposure contributes to the development of allergic sensitization in children and adolescents up to 16 years of age.METHODS: We included 3316 children from a birth cohort followed for 16 years. SHS exposure and symptoms of allergic disease were assessed using repeated parental questionnaires. Serum immunoglobulin E against eight common inhalant and six food allergens was assessed at ages 4, 8, and 16 years with ImmunoCAP. The association between SHS exposure and sensitization was explored using logistic regression and generalized estimating equations.RESULTS: Exposure to SHS in infancy without prior exposure in utero, was associated with an excess risk of food sensitization at age 4 (OR 1.47, 95% CI 1.08-2.00), with comparable ORs at ages 8 and 16 years. In longitudinal analyses, an overall association was indicated between SHS in infancy and food sensitization up to age 16 years (OR 1.24, 95% CI 0.98-1.56). Maternal smoking during pregnancy was unrelated to sensitization up to 16 years of age. When sensitization was combined with concurrent symptoms of allergic disease, SHS in infancy was associated with an overall elevated risk of eczema with sensitization (OR 1.62, 95% CI 1.20-2.18).CONCLUSIONS: SHS exposure in infancy appears to increase the risk of sensitization to food allergens up to age 16 years as well as eczema in combination with sensitization.
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| 43. |
- Thacher, Jesse D., et al.
(författare)
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Pre- and Postnatal Exposure to Parental Smoking and Allergic Disease Through Adolescence
- 2014
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Ingår i: Pediatrics. - : American Academy of Pediatrics (AAP). - 0031-4005 .- 1098-4275. ; 134:3, s. 428-434
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To examine the role of prenatal and postnatal second-hand tobacco smoke (SHS) exposure on asthma, rhinitis, and eczema development up to 16 years of age. METHODS: A birth cohort of 4089 children was followed for 16 years. Information on parental smoking habits, lifestyle factors, and symptoms of allergic disease was gathered using repeated parental questionnaires. Generalized estimating equations assessed the overall and age-specific associations between SHS exposure and allergic disease at ages 1 to 16 years. RESULTS: Exposure to SHS in utero was associated with an overall elevated risk of developing asthma up to 16 years (odds ratio [OR] = 1.45; 95% confidence interval [CI], 1.15-1.83) but not for rhinitis or eczema. After additional adjustment for parental smoking throughout childhood, excess overall risks for asthma remained statistically significant. Moreover, a dose-dependent pattern with SHS was observed. Exposure to SHS during infancy was associated with an overall elevated risk of asthma (OR = 1.23; 95% CI, 1.01-1.51), rhinitis (OR = 1.18; 95% CI, 1.01-1.39), and eczema (OR = 1.26; 95% CI, 1.09-1.45) up to 16 years. When age-specific associations were examined, the elevated risks related to SHS exposure in utero or during infancy were mostly confined to early childhood for asthma and rhinitis, whereas the excess risk of eczema appeared greatest at later ages. CONCLUSIONS: Our findings indicate that early SHS exposure, in utero or during infancy, influences the development of allergic disease up to adolescence. Excess risks for asthma and rhinitis were seen primarily in early childhood, whereas those for eczema occurred at later ages.
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| 44. |
- Webb, Robert, et al.
(författare)
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Sustainable urban systems : Co-design and framing for transformation
- 2018
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Ingår i: Ambio. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 47:1, s. 57-77
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Tidskriftsartikel (refereegranskat)abstract
- Rapid urbanisation generates risks and opportunities for sustainable development. Urban policy and decision makers are challenged by the complexity of cities as social-ecological-technical systems. Consequently there is an increasing need for collaborative knowledge development that supports a whole-of-system view, and transformational change at multiple scales. Such holistic urban approaches are rare in practice. A co-design process involving researchers, practitioners and other stakeholders, has progressed such an approach in the Australian context, aiming to also contribute to international knowledge development and sharing. This process has generated three outputs: (1) a shared framework to support more systematic knowledge development and use, (2) identification of barriers that create a gap between stated urban goals and actual practice, and (3) identification of strategic focal areas to address this gap. Developing integrated strategies at broader urban scales is seen as the most pressing need. The knowledge framework adopts a systems perspective that incorporates the many urban trade-offs and synergies revealed by a systems view. Broader implications are drawn for policy and decision makers, for researchers and for a shared forward agenda.
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