151 research outputs found
A new algorithm for the determination of differential taxa
No full textHow can we determine differential taxa in a vegetation data set? The new algorithm presented here uses an intuitive fidelity threshold based on relative constancy differences. It is tested on a simulated and a real data set. The results of the proposed algorithm are discussed in comparison with other methods used for the determination of differential taxa. The new algorithm defines each taxon in each group of relevEs as: (1) positively differentiating, (2) positively-negatively differentiating, (3) negatively differentiating, or (4) non-differentiating. Each taxon in a data set may be: (1) positively, positively-negatively or negatively differentiating for each group in the data set, (2) differentiating for some groups and non-differentiating for the remaining groups, or (3) non-differentiating for all groups in the data set. The new algorithm finds the relevE groups that are positively differentiated against other groups that are negatively differentiated. It reveals differentiating structures in the data set and thus makes quantification of the relations among and between different syntaxonomic ranks conceivable. As it distinguishes between different types of differential taxa, it might improve standards of typification in vegetation classification
Hellenic Woodland Database
No full textThe Hellenic Woodland Database (GIVD ID EU-GR-006) includes relevés from 59 sources, approximately, as well as unpublished relevés. In total 4,571 relevés have already been entered in the database, but the database is going to continue growing in the near future. Species abundances are recorded according the 7-grade Braun-Blanquet scale. The oldest relevés date back to 1963. For the majority of relevés (more than 90%) environmental data (e.g. altitude, slope aspect, inclination) exist. Relevés entered in the database represent both evergreen and deciduous forests, as well as scrubs and they belong (according to the original publications) to the classes Quercetea ilicis, Rhamno-Prunetea spinosae, Erico-Pinetea, Quercetea pubescentis, Querco-Fagetea, Vaccinio-Piceetea and Populetea albae. Most relevés (approximately 69%) concern northern Greece (floristic regions of northeastern, north-central Greece and northern Pindos), while the remainder concern the rest of Greek mainland as well as the islands
Optimal TNFS-secure pairings on elliptic curves with composite embedding degree
No full textIn this paper we present a comprehensive comparison between pairing-friendly elliptic curves, considering di erent curve forms and twists where possible. We de ne an additional measure of the e- ciency of a parametrized pairing-friendly family that takes into account the number eld sieve (NFS) attacks (unlike the -value). This measure includes an approximation of the security of the discrete logarithm problem in F pk , computed via the method of Barbulescu and Duquesne [4]. We compute the security of the families presented by Fotiadis and Konstantinou in [14], compute some new families, and compare the eciency of both of these with the (adjusted) BLS, KSS, and BN families, and with the new families of [20]. Finally, we recommend pairing-friendly elliptic curves for security levels 128 and 192
Vegetation types with Quercus ithaburensis subsp. macrolepis in Greece
No full textQuercus ithaburensis subsp. macrolepis is an important component of the Mediterranean flora, forming distinctive forests in the thermo and meso Mediterranean vegetation zone. The purpose of this study was to investigate the structure of Q. ithaburensis subsp. macrolepis communities of mainland and insular Greece, from a phytoecological point of view. The identification followed the Braun-Blanquet method and was based on 138 records from 19 areas. Seventeen vegetation types with Q. ithaburensis subsp. macrolepis have been distinguished in which the species holds a dominant, sub-dominant or differential role. All these groupments are attached to the class Quercetea ilicis distinguished in forest units of the Quercetalia ilicis (Quercion ilicis alliance) and pre-forest units of the Pistacio-Rhamnetalia alaterni (Ceratonio-Rhamnion and Pistacio-Rhamnion alliances) orders, while some very degraded communities, are difficult to be classified from a phytosociological point of view. Several diagnostic species of other phytosociological classes also appear, reflecting the impacts that these communities have undergone. The life form spectrum of these communities shows that therophytes are the most represented while for the chorological spectrum, the Mediterranean element is dominant.Theocharopoulos Michalis, Pantera Anastasia, Fotiadis Georgios, Papadopoulos Andreas. Vegetation types with Quercus ithaburensis subsp. macrolepis in Greece. In: Ecologia mediterranea, tome 46 n°1, 2020. pp. 17-40
Distribution and phytogeographical analysis of Quercus ithaburensis ssp. macrolepis in Greece
No full textThis paper presents the distribution of Q. ithaburensis
ssp. macrolepis in Greece, its basic ecological requirements such as rock and soil characteristics, topography, climatic and bioclimatic factors and chorological and life form spectra of its forests. Data were collected with questionnaires sent to all Forest Service offices around the country and were further completed with field observations. The results suggest that Q. ithaburensis ssp. macrolepis forests cover an area of 29,631.8 ha in the form of stands, thickets and groups, in lowlands and uplands of continental and insular Greece. Furthermore, isolated individuals are scattered throughout the country. The subspecies develops in a variety of rock and soil types, slope inclinations, aspects and different types of Mediterranean bioclimates. It prefers low to middle altitudes, on the sub-humid bioclimate and on shallow to moderate deep calcareous soils. All these characteristics, combined with human activities, influence vegetation types in each region. Due to climate and various human interventions, the Mediterranean elements dominate and only in the forests found in the more northern regions the percentage of the submeditteranean elements increase considerably. Additionally, Q. ithaburensis
ssp. macrolepis forests are characterized by the dominance of therophytes.Cet article présente la distribution de Q. ithaburensis
ssp. macrolepis en Grèce, ses conditions écologiques de base, telles que les caractéristiques du substrat et du sol, la topographie, les facteurs climatiques et bioclimatiques et des spectres chorologiques et des formes de vie. Les données ont été collectées à l’aide des questionnaires, envoyés à tous les services forestiers du pays et complétés par des observations et mesures sur le terrain. Les résultats montrent que Q. ithaburensis ssp. macrolepis couvrent une superficie de 29 631,8 ha, en formations forestières, dans les zones de plaines et semimontagneuses de la Grèce continentale et insulaire. Il est encore présent sous la forme d’arbres isolés dans plusieurs régions du pays. La sous-espèce se développe sur divers types de substrat et de sols avec des inclinaisons et expositions diverses, et sous différents types de bioclimats méditerranéens. Elle préfère des régions à basse et moyenne altitude, en bioclimat subhumide, sur des sols calcaires peu ou moyennement profonds. Tous ces critères combinés aux activités humaines influencent les structures de végétation dans chaque région. En raison du climat et des divers types d’interventions humaines, les éléments méditerranéens dominent. C’est seulement dans les forêts du nord du pays, que le pourcentage des éléments subméditerranéens augmente considérablement. En générale les forêts de Q. ithaburensis ssp. macrolepis sont caractérisées par la dominance des thérophytes.Pantera Anastasia, Papadopoulos Andreas, Fotiadis Georgios, Papanastasis Vasilios P. Distribution and phytogeographical analysis of Quercus ithaburensis ssp. macrolepis in Greece. In: Ecologia mediterranea, tome 34,2008. pp. 73-82
Optimal TNFS-secure pairings on elliptic curves with even embedding degree
No full textIn this paper we give a comprehensive comparison between pairing-friendly elliptic curves in Jacobi Quartic and Edwards form with quadratic, quartic, and sextic twists. Our comparison looks at the best choices to date for pairings on elliptic curves with even embedding degree on both G 1 ×G 2 \u3cbr/\u3eG1×G2\u3cbr/\u3e and G 2 ×G 1 \u3cbr/\u3eG2×G1\u3cbr/\u3e (these are the twisted Ate pairing and the optimal Ate pairing respectively). We apply this comparison to each of the nine possible 128-bit TNFS-secure families of elliptic curves computed by Fotiadis and Konstantinou; we compute the optimal choice for each family together with the fastest curve shape/pairing combination. Comparing the nine best choices from the nine families gives a optimal choice of elliptic curve, shape and pairing (given current knowledge of TNFS-secure families). We also present a proof-of-concept MAGMA implementation for each case. Additionally, we give the first analysis, to our knowledge, of the use of quadratic twists of both Jacobi Quartic and Edwards curves for pairings on G 2 ×G 1 \u3cbr/\u3eG2×G1\u3cbr/\u3e, and of the use of sextic twists on Jacobi Quartic curves on G 1 ×G 2 \u3cbr/\u3eG1×G2\u3cbr/\u3e
Classification of the high‐rank syntaxa of the Central and Eastern Balkan dry grasslands with a new hierarchical expert system approach
No full textAbstract Aims Developing a hierarchical classification system for classes, orders and alliances of the diverse dry grasslands of the Central and Eastern Balkan Peninsula and translating this into an electronic expert system (ES) for the automatic assignment of plots. Location Serbia, Kosovo, North Macedonia, Bulgaria and northern Greece. Methods We extracted 5734 plots from the Balkan Dry Grassland Database corresponding to eight classes of dry grasslands reported from the region, using the EuroVegChecklist ES. This data set and later the plots within each derived subunit were subjected to a new numerical approach: starting with an initial partitioning (expert‐interpreted TWINSPAN classification), diagnostic species were determined based on their phi‐values for the target vegetation type and the differences in phi‐values to the next similar types. These diagnostic species were fed into an ES to create a new partitioning, a procedure which was iterated until diagnostic species and species of the ES converged. Then the same approach was applied within each of the derived units to define the units of the next‐lower level. Results The iterative cluster optimisation (ICO) converged in all cases. The resulting hierarchical expert system (HES) classified 95% of all plots to alliances. We distinguished four classes with eight orders and 12 alliances: (1) Tuberarietea guttatae ( Romuleion ); (2) Stipo‐Brachypodietea distachyi ( Clinopodio alpini‐Thymion striati ); (3) Festuco‐Brometea with Brachypodietalia pinnati ( Chrysopogono‐Danthonion calycinae and Cirsio‐Brachypodion pinnati ), Festucetalia valesiacae ( Festucion valesiacae ), an unnamed order of rocky steppes (with Pimpinello‐Thymion zygioidis ) and Koelerietalia splendentis ( Centaureo‐Bromion fibrosi , Saturejion montanae and Diantho haematocalycis‐Festucion hirtovaginatae ); (four) Koelerio‐Corynephoretea with Sedo acris‐Festucetalia ( Festucion vaginatae ) and Trifolio arvensis‐Festucetalia ovinae ( Armerio rumelicae‐Potentillion and Minuartio montanae‐Poion molinerii all. nov. ). Conclusions We created a unified hierarchical classification with an electronic ES using diagnostic species defined by phi‐values. Our new approach (ICO‐HES: iterative cluster optimisation for hierarchical expert systems) allows dividing large data sets into meaningful units at several hierarchical levels, and thus has high potential for complex classifications. Importantly, it overcomes the divide between ES species and diagnostic species and re‐unites them into one concept.Grantová Agentura České Republiky https://doi.org/10.13039/50110000182
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No full textSupport of Future Disaster Response Using Generalized Access Networks (GANs)
No full textEfficient communication and coordination are major challenges experienced by the emergency services (firebrigade, police, ambulance) during the first response to a major incident. A major incident can happen anywhere and at any time, hence support for emergency communications services should be ubiquitous and independent of communication technologies and infrastructure used. We present a vision of how ambient intelligent environments may be used in the future to support the emergency services during first response to a major incident. Support includes enabling emergency communications and biomedical monitoring for front line personnel. In this paper we focus on the possibilities and challenges raised by using the GAN (Generalized Access Network) infrastructure to support ambient intelligent services and emergency services (fire-brigade, police, ambulance) for major incident management
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