Performance comparison of point and spatial access methods

In the past few years a large number of multidimensional point access methods, also called multiattribute index structures, has been suggested, all of them claiming good performance. Since no performance comparison of these structures under arbitrary (strongly correlated nonuniform, short "ugly") data distributions and under various types of queries has been performed, database researchers and designers were hesitant to use any of these new point access methods. As shown in a recent paper, such point access methods are not only important in traditional database applications. In new applications such as CAD/CIM and geographic or environmental information systems, access methods for spatial objects are needed. As recently shown such access methods are based on point access methods in terms of functionality and performance. Our performance comparison naturally consists of two parts. In part I we w i l l compare multidimensional point access methods, whereas in part I I spatial access methods for rectangles will be compared. In part I we present a survey and classification of existing point access methods. Then we carefully select the following four methods for implementation and performance comparison under seven different data files (distributions) and various types of queries: the 2-level grid file, the BANG file, the hB-tree and a new scheme, called the BUDDY hash tree. We were surprised to see one method to be the clear winner which was the BUDDY hash tree. It exhibits an at least 20 % better average performance than its competitors and is robust under ugly data and queries. In part I I we compare spatial access methods for rectangles. After presenting a survey and classification of existing spatial access methods we carefully selected the following four methods for implementation and performance comparison under six different data files (distributions) and various types of queries: the R-tree, the BANG file, PLOP hashing and the BUDDY hash tree. The result presented two winners: the BANG file and the BUDDY hash tree. This comparison is a first step towards a standardized testbed or benchmark. We offer our data and query files to each designer of a new point or spatial access method such that he can run his implementation in our testbed

Co-designing the knowledge management model

This work-in-progress study reviews co-designing processes through the lens of possibility-driven design (PDD). A knowledge management model (KMM) is co-designed by facilitating the development work of senior and regional innovation actors who share ideas, experience and information in the development of smart products and services for an age-friendly smart living environment. The empirical part is divided into three stages: an orientation workshop, two panel meetings and three co-design and validation workshops where an appropriate knowledge management model is co-designed through iteration rounds. The first stage maps the regional innovation actors, relevant organisations in the region and data flows between all the parties. Ideas of suitable ways to manage knowledge are gathered from the panel meetings of the second stage and are methodologically supported by the strategic options development and analysis (SODA) approach. At the time of writing this paper, the third stage consisting of three workshops with appropriate iteration rounds is on-going. The findings of the study provide insights regarding the use of PDD activities with an inclusion of the SODA approach when facilitating the co-design of a KMM with a multi-professional group of experts. The study contributes to the theory of PDD by integrating systematic methodological aspects to it when working on complex problems.info:eu-repo/semantics/publishedVersio

Quantification of uncertainty in aerosol optical thickness retrieval arising from aerosol microphysical model and other sources, applied to Ozone Monitoring Instrument (OMI) measurements

Satellite instruments are nowadays successfully utilised for measuring atmospheric aerosol in many applications as well as in research. Therefore, there is a growing need for rigorous error characterisation of the measurements. Here, we introduce a methodology for quantifying the uncertainty in the retrieval of aerosol optical thickness (AOT). In particular, we concentrate on two aspects: uncertainty due to aerosol microphysical model selection and uncertainty due to imperfect forward modelling. We apply the introduced methodology for aerosol optical thickness retrieval of the Ozone Monitoring Instrument (OMI) on board NASA's Earth Observing System (EOS) Aura satellite, launched in 2004. We apply statistical methodologies that improve the uncertainty estimates of the aerosol optical thickness retrieval by propagating aerosol microphysical model selection and forward model error more realistically. For the microphysical model selection problem, we utilise Bayesian model selection and model averaging methods. Gaussian processes are utilised to characterise the smooth systematic discrepancies between the measured and modelled reflectances (i.e. residuals). The spectral correlation is composed empirically by exploring a set of residuals. The operational OMI multi-wavelength aerosol retrieval algorithm OMAERO is used for cloud-free, over-land pixels of the OMI instrument with the additional Bayesian model selection and model discrepancy techniques introduced here. The method and improved uncertainty characterisation is demonstrated by several examples with different aerosol properties: weakly absorbing aerosols, forest fires over Greece and Russia, and Sahara desert dust. The statistical methodology presented is general; it is not restricted to this particular satellite retrieval application

Increasing fruit and vegetable consumption in Ireland

Context: Following recommended dietary guidelines, Ireland has since 2010 implemented a  0% Value Added Tax (VAT) on fruits and vegetables to increase consumption. Eleven years after policy implementation, the Irish still do not meet recommended intake for fruit and vegetable consumption, consuming 3.9 portions a day compared to 7 daily portions recommended. Policy Options: Four alternatives for improvement were assessed and compared:            1) retain the status quo of reduced VAT for healthy foods, 2) VAT only for locally produced fruits and vegetables, 3) increased VAT for salty and sweet foods with a subsidy for fruits and vegetables, and 4) an education-based policy. Four evaluation criteria were applied for the comparison: economic feasibility, effectiveness, political feasibility, and equity. Recommendations: The status quo remains the best option for Ireland. However, further assessment of this 0% VAT policy on fruits and vegetables is warranted, pending the availability of additional data to enable an in-depth understanding of policy implementation. &nbsp

Archaea are prominent members of the prokaryotic communities colonizing common forest mushrooms

In this study, the abundance and composition of prokaryotic communities associated with the inner tissue of fruiting bodies of Suillus bovinus, Boletus pinophilus, Cantharellus cibarius, Agaricus arvensis, Lycoperdon perlatum, and Piptoporus betulinus were analyzed using culture-independent methods. Our findings indicate that archaea and bacteria colonize the internal tissues of all investigated specimens and that archaea are prominent members of the prokaryotic community. The ratio of archaeal 16S rRNA gene copy numbers to those of bacteria was >1 in the fruiting bodies of four out of six fungal species included in the study. The largest proportion of archaeal 16S rRNA gene sequences belonged to thaumarchaeotal classes Terrestrial group, Miscellaneous Crenar-chaeotic Group (MCG), and Thermoplasmata. Bacterial communities showed characteristic compositions in each fungal species. Bacterial classes Gammaproteobacteria, Actinobacteria, Bacilli, and Clostridia were prominent among communities in fruiting body tissues. Bacterial populations in each fungal species had different characteristics. The results of this study imply that fruiting body tissues are an important habitat for abundant and diverse populations of archaea and bacteria.Peer reviewe

Evolution of competitive ability for essential resources

Competition for limiting resources is among the most fundamental ecological interactions and has long been considered a key driver of species coexistence and biodiversity. Species’ minimum resource requirements, their R*, are key traits that link individual physiological demands to the outcome of competition. However, a major question remains unanswered -- to what extent are species’ competitive traits able to evolve in response to resource limitation? To address this knowledge gap, we performed an evolution experiment in which we exposed Chlamydomonas reinhardtii for approximately 285 generations to seven environments in chemostats which differed in resource supply ratios (including nitrogen, phosphorus and light limitation) and salt stress. We then grew the ancestors and descendants in common garden experiments and quantified their competitive abilities for essential resources. We investigated constraints on trait evolution by testing whether changes in resource requirements for different resources were correlated. Competitive abilities for phosphorus improved in all populations, while competitive abilities for nitrogen and light increased in some populations and decreased in others. In contrast to the common assumption that there are trade-offs between competitive abilities for different resources, we found that improvements in competitive ability for a resource came at no detectable cost. Instead, improvements in competitive ability for multiple resources were either positively correlated or not significantly correlated. Using resource competition theory, we then demonstrated that rapid adaptation in competitive traits altered the predicted outcomes of competition. These results highlight the need to incorporate contemporary evolutionary change into predictions of competitive community dynamics over environmental gradients