Economists are not dismal, the world is not a Petri dish and other reasons for optimism

One of the recurrent themes in the debate around how to ensure global food security concerns the capacity of the planet to support its growing population. Neo-Malthusian thinking suggests that we are in a situation in which further expansion of the population cannot be supported and that the population checks, with their dismal consequences envisaged by Malthus, will lead to a new era of stagnant incomes and population. More sophisticated models of the link between population and income are less gloomy however. They see population growth as an integral component of the economic growth which is necessary to ensure that the poorest achieve food security. An undue focus on the difficulties of meeting the demands of the increasing population risks damaging this growth. Instead, attention should be focused on ensuring that the conditions to ensure that economic growth accompanies population growth are in place.

Replacing Norway spruce with European beech: a comparison of biomass and Net Primary Production patterns in young stands

An alteration of species composition in temperate forests – both managed and natural - is one of the expected effects of environmental change. Present forest tree species ranges will be altered by changing environmental conditions. By a combination of continuous and destructive sampling, we compared biomass stocks and annual NPP in naturally regenerated stands of Norway spruce and European beech. We purposely selected a site where future environmental conditions are predicted to favour beech over presently dominant spruce. We found no difference in overall productivity, but biomass allocation differed significantly between the two species. Beech allocated more assimilates to stem and roots than spruce. There was no significant difference between the species in NPP of the fast turnover biomass pool comprising foliage and fine roots. Maximum height growth occurred about a month earlier than in spruce, potentially changing the timing of carbon (C) flow into the soil pools. We show that the replacement of spruce by beech will result in changes in forest biomass allocation and in alterations of belowground C cycle. Such changes will affect forest ecosystem function by modifying the magnitude and timing of certain C fluxes, but also by potentially changing the species composition of forest biota dependent on them.

Elastic-net prefiltering for two-class classification

A two-stage linear-in-the-parameter model construction algorithm is proposed aimed at noisy two-class classification problems. The purpose of the first stage is to produce a prefiltered signal that is used as the desired output for the second stage which constructs a sparse linear-in-the-parameter classifier. The prefiltering stage is a two-level process aimed at maximizing a model's generalization capability, in which a new elastic-net model identification algorithm using singular value decomposition is employed at the lower level, and then, two regularization parameters are optimized using a particle-swarm-optimization algorithm at the upper level by minimizing the leave-one-out (LOO) misclassification rate. It is shown that the LOO misclassification rate based on the resultant prefiltered signal can be analytically computed without splitting the data set, and the associated computational cost is minimal due to orthogonality. The second stage of sparse classifier construction is based on orthogonal forward regression with the D-optimality algorithm. Extensive simulations of this approach for noisy data sets illustrate the competitiveness of this approach to classification of noisy data problems.

Particle swarm optimisation assisted classification using elastic net prefiltering

A novel two-stage construction algorithm for linear-in-the-parameters classifier is proposed, aiming at noisy two-class classification problems. The purpose of the first stage is to produce a prefiltered signal that is used as the desired output for the second stage to construct a sparse linear-in-the-parameters classifier. For the first stage learning of generating the prefiltered signal, a two-level algorithm is introduced to maximise the model's generalisation capability, in which an elastic net model identification algorithm using singular value decomposition is employed at the lower level while the two regularisation parameters are selected by maximising the Bayesian evidence using a particle swarm optimization algorithm. Analysis is provided to demonstrate how “Occam's razor” is embodied in this approach. The second stage of sparse classifier construction is based on an orthogonal forward regression with the D-optimality algorithm. Extensive experimental results demonstrate that the proposed approach is effective and yields competitive results for noisy data sets.

Evidence of increased net ecosystem productivity associated with a longer vegetated season in a deciduous forest in south-central Indiana, USA

Observations of net ecosystem exchange (NEE) of carbon and its biophysical drivers have been collected at the AmeriFlux site in the Morgan-Monroe State Forest (MMSF) in Indiana, USA since 1998. Thus, this is one of the few deciduous forest sites in the world, where a decadal analysis on net ecosystem productivity (NEP) trends is possible. Despite the large interannual variability in NEP, the observations show a significant increase in forest productivity over the past 10 years (by an annual increment of about 10 g C m−2 yr−1). There is evidence that this trend can be explained by longer vegetative seasons, caused by extension of the vegetative activity in the fall. Both phenological and flux observations indicate that the vegetative season extended later in the fall with an increase in length of about 3 days yr−1 for the past 10 years. However, these changes are responsible for only 50% of the total annual gain in forest productivity in the past decade. A negative trend in air and soil temperature during the winter months may explain an equivalent increase in NEP through a decrease in ecosystem respiration.

Elastic net orthogonal forward regression

An efficient two-level model identification method aiming at maximising a model׳s generalisation capability is proposed for a large class of linear-in-the-parameters models from the observational data. A new elastic net orthogonal forward regression (ENOFR) algorithm is employed at the lower level to carry out simultaneous model selection and elastic net parameter estimation. The two regularisation parameters in the elastic net are optimised using a particle swarm optimisation (PSO) algorithm at the upper level by minimising the leave one out (LOO) mean square error (LOOMSE). There are two elements of original contributions. Firstly an elastic net cost function is defined and applied based on orthogonal decomposition, which facilitates the automatic model structure selection process with no need of using a predetermined error tolerance to terminate the forward selection process. Secondly it is shown that the LOOMSE based on the resultant ENOFR models can be analytically computed without actually splitting the data set, and the associate computation cost is small due to the ENOFR procedure. Consequently a fully automated procedure is achieved without resort to any other validation data set for iterative model evaluation. Illustrative examples are included to demonstrate the effectiveness of the new approaches.

Changes in global net radiative imbalance 1985-2012

Combining satellite data, atmospheric reanalyses and climate model simulations, variability in the net downward radiative flux imbalance at the top of Earth's atmosphere (N) is reconstructed and linked to recent climate change. Over the 1985-1999 period mean N (0.34 ± 0.67 Wm–2) is lower than for the 2000-2012 period (0.62 ± 0.43 Wm–2, uncertainties at 90% confidence level) despite the slower rate of surface temperature rise since 2000. While the precise magnitude of N remains uncertain, the reconstruction captures interannual variability which is dominated by the eruption of Mt. Pinatubo in 1991 and the El Niño Southern Oscillation. Monthly deseasonalized interannual variability in N generated by an ensemble of 9 climate model simulations using prescribed sea surface temperature and radiative forcings and from the satellite-based reconstruction is significantly correlated (r ∼ 0.6) over the 1985-2012 period.

Rationality of service composition of Workflow Net in a service oriented architecture

Users’ requirements change drives an information system evolution. Consequently, such evolution affects those atomic services which provide functional operations from one state of their composition to another state of composition. A challenging issue associated with such evolution of the state of service composition is to ensure a resultant service composition remaining rational. This paper presents a method of Service Composition Atomic-Operation Set (SCAOS). SCAOS defines 2 classes of atomic operations and 13 kinds of basic service compositions to aid a state change process by using Workflow Net. The workflow net has algorithmic capabilities to compose the required services with rationality and maintain any changes to the services in a different composition also rational. This method can improve the adaptability to the ever changing business requirements of information systems in the dynamic environment.

Joint data assimilation of satellite reflectance and net ecosystem exchange data constrains ecosystem carbon fluxes at a high-elevation subalpine forest

We utilized an ecosystem process model (SIPNET, simplified photosynthesis and evapotranspiration model) to estimate carbon fluxes of gross primary productivity and total ecosystem respiration of a high-elevation coniferous forest. The data assimilation routine incorporated aggregated twice-daily measurements of the net ecosystem exchange of CO2 (NEE) and satellite-based reflectance measurements of the fraction of absorbed photosynthetically active radiation (fAPAR) on an eight-day timescale. From these data we conducted a data assimilation experiment with fifteen different combinations of available data using twice-daily NEE, aggregated annual NEE, eight-day f AP AR, and average annual fAPAR. Model parameters were conditioned on three years of NEE and fAPAR data and results were evaluated to determine the information content from the different combinations of data streams. Across the data assimilation experiments conducted, model selection metrics such as the Bayesian Information Criterion and Deviance Information Criterion obtained minimum values when assimilating average annual fAPAR and twice-daily NEE data. Application of wavelet coherence analyses showed higher correlations between measured and modeled fAPAR on longer timescales ranging from 9 to 12 months. There were strong correlations between measured and modeled NEE (R2, coefficient of determination, 0.86), but correlations between measured and modeled eight-day fAPAR were quite poor (R2 = −0.94). We conclude that this inability to determine fAPAR on eight-day timescale would improve with the considerations of the radiative transfer through the plant canopy. Modeled fluxes when assimilating average annual fAPAR and annual NEE were comparable to corresponding results when assimilating twice-daily NEE, albeit at a greater uncertainty. Our results support the conclusion that for this coniferous forest twice-daily NEE data are a critical measurement stream for the data assimilation. The results from this modeling exercise indicate that for this coniferous forest, average annuals for satellite-based fAPAR measurements paired with annual NEE estimates may provide spatial detail to components of ecosystem carbon fluxes in proximity of eddy covariance towers. Inclusion of other independent data streams in the assimilation will also reduce uncertainty on modeled values.

Combining satellite observations and reanalysis energy transports to estimate global net surface energy fluxes 1985-2012

Two methods are developed to estimate net surface energy fluxes based upon satellite-based reconstructions of radiative fluxes at the top of atmosphere and the atmospheric energy tendencies and transports from the ERA-Interim reanalysis. Method 1 applies the mass adjusted energy divergence from ERA-Interim while method 2 estimates energy divergence based upon the net energy difference at the top of atmosphere and the surface from ERA-Interim. To optimise the surface flux and its variability over ocean, the divergences over land are constrained to match the monthly area mean surface net energy flux variability derived from a simple relationship between the surface net energy flux and the surface temperature change. The energy divergences over the oceans are then adjusted to remove an unphysical residual global mean atmospheric energy divergence. The estimated net surface energy fluxes are compared with other data sets from reanalysis and atmospheric model simulations. The spatial correlation coefficients of multi-annual means between the estimations made here and other data sets are all around 0.9. There are good agreements in area mean anomaly variability over the global ocean, but discrepancies in the trend over the eastern Pacific are apparent.

Utveckling av karttjänst i ASP.NET

Syftet med projektet var att tillverka en webbaserad kartvisningstjänst för att visualisera geografiska och infrastrukturella förändringar över tiden. Detta genom att historiska och dagsaktuella kartor överlappas och presenteras som en bild.Applikationen utvecklades i ASP.NET med programspråket Visual Basic. Som databashanterare användes Microsoft SQL-server 2000. För bearbetning av kartmaterialet användes Arcview 8. Som utvecklingsmetod användes David Siegels modell för att konstruera webbplatser. Rapporten tar upp Ben Schniedermans principer för att skapa användarvänliga webbapplikationer.Examensarbetet genomfördes våren 2004 vid Högskolan Dalarna, campus Framtidsdalen, Borlänge.

Webbaserattidbokningssystem med ASP.net

Vi fick av netweb.se uppdraget att tillverka ett webbaserat tidbokningssystem. Detta tidbokningssystem skulle vara möjligt att applicera på många olika typer av verksamheter. Kunden framlade ett önskemål om att systemet skulle byggas i ASP.net.Tillsammans med detta system har vi även fördjupat oss i användbarhet och utnyttjat denna studie till att göra ett användbarhetstest. Resultaten av testet har utvärderats och applicerats på systemet.Projektet ledde till ett färdigt tidbokningssystem. Resultatet av användbarhetstestet visade på skillnader mellan yrkesgrupper, där människor inom databranschen hade störst svårigheter att ta till sig systemet. Anledningar till detta kan vara att utvecklare och datatekniker fokuserar på fel saker när de bedömer ett system, samt inte tänker som en användare. Även skillnader mellan kön och åldersgrupper visade sig i resultatet av användbarhetstestet.

Konstruktion av en Marknadsplats i .NET för Högskolan Dalarna

Vi har i vårat examensarbete tagit fram en e-marknadsplats i för Högskolan Dalarna. Marknadsplatsen är programmerad i asp.NET och vb.NET. Fram tills idag har skolans anslagstavlor använts flitigt för annonsering av, inte bara studentlitteratur, utan allt från pennor till bilar. Högskolan Dalarna har därför en önskan om att få en e-marknadsplats där studenter har möjlighet att annonsera.