ОПТИМАЛЬНАЯ МАРШРУТИЗАЦИЯ ИНФОРМАЦИОННЫХ ПОТОКОВ С УЧЕТОМ ПАРАМЕТРОВ QOS

A classification of traffic in IP-based networks is described. The problem of traffic within the parameters of quality of service is formulated. The algorithms to maximize flow and minimize cost are reviewed. The algorithm of the problem of the «maximum minimum cost flow» is modificated so that would be taken into account when choosing a path not only cost, but also the delay. Implementation of this algorithm in Java is developed. The program to test the algorithm with the ability to model the characteristics of the network is written.Приведена классификация трафика в IP-сетях. Сформулирована проблема передачи трафика с учетом параметров качества обслуживания. Рассмотрены алгоритмы максимизации потока и минимизации стоимости. Модифицирован алгоритм из задачи о "Максимальном потоке минимальной стоимости" так, чтобы при выборе пути учитывалась не только стоимость, но и задержка. Произведена реализация данного алгоритма на языке Java. Написана программа для проверки работы алгоритма с возможностью моделирования характеристик сети

Paleobiología del género Hypericum (Hypericaceae): una revisión del registro fósil y sus implicaciones paleogeográficas

Genus Hypericum is one of the 100 largest genera in angiosperms with nearly 500 species. Despite its worldwide, nearly cosmopolitan distribution and apparently old age – there are fossil remains of relatives from the Mid Cretaceous - the fossil record of Hypericum has been largely overlooked in phylogenetic studies. Here, we survey the fossil record of Hypericum from the literature, with special emphasis on the oldest fossil remain, Hypericum antiquum, from which we reassess its diagnostic characters. We evaluate the implications of this record in reconstructing the past geographic distribution of genus Hypericum.El género Hypericum contiene 500 especies aproximadamente y es uno de los 100 géneros más grandes dentro de las angiospermas. A pesar de que tiene una distribución cosmopolita y de que es presumiblemente muy antiguo –existen restos fósiles de grupos emparentados filogenéticamente del Cretácico medio– el registro fósil de Hypericum no ha sido utilizado en estudios filogenéticos. En este trabajo hacemos una revisión de la literatura sobre el registro fósil de Hypericum con especial énfasis en los restos más antiguos de la especie Hypericum antiquum, del que reevaluamos sus caracteres diagnósticos. Finalmente, discutimos las implicaciones que este registro fósil tiene en la reconstrucción paleogeográfica del género Hypericum

The first Pleistocene fossil records of Urtica kioviensis Rogow. (Urticaceae) and Potamogeton sukaczevii Wieliczk. (Potamogetonaceae) in the British Isles

Seeds of the extant Urtica kioviensis Rogow. (Urticaceae) and endocarps of the extinct Potamogeton sukaczevii Wieliczk. (Potamogetonaceae) were recorded in diverse plant macrofossil assemblages recovered from organic sediments exposed during excavations at Saham Toney, Norfolk, UK. Aminostratigraphical data show the sediments were deposited during the Ipswichian (Last Interglacial) Stage. Palynological data indicates deposition during the Carpinus pollen zone of the Ipswichian Stage—the latter part of pollen zone Ip IIb and Ip III. The records are noteworthy not only because they are the first in the British Pleistocene but also because of the geographical occurrences of these two species. Urtica kioviensis is absent from the British flora today and has a modern range in central and eastern Europe (only extending as far west as north–east Germany and Denmark), while the extinct Potamogeton sukaczevii has only been recovered from Late Pleistocene sediments in Belarus, Lithuania, Poland and western Russia. The presence of U. kioviensis along with other exotic species to the British Isles (e.g. Najas minor L. and Salvinia natans L., which today have central and southern ranges in Europe and in the case of S. natans occurs on other continents) may point to more continental conditions or warmer summer conditions during the second half of the Ipswichian Stage in southern Britain. No modern analogues occur in Britain for the assemblages recovered from Saham Toney. Evidence of colder winters or at least warmer summers at the time of deposition does not support the view that sea-level peaked in the Carpinus zone of the Eemian Stage (correlated with the Ipswichian Stage) associated with increased oceanicity. Southern Britain would have been under the influence of the Atlantic Ocean and a degree of oceanicity is supported by the presence of two thermophilous taxa, Hedera and Ilex, in the pollen spectra from Saham Toney. Alternative explanations for the presence of these exotic species are that they were tolerating mild winters and cooler summers at the time of deposition or exploiting suitable micro-environments. The distribution of P. sukaczevii is probably an artefact of the distribution of expertise in the identification of Potamogeton fossil endocarps rather than having any palaeogeographic or palaeoclimatic significance. It is an extinct ancestor of the extant P. maackianus A. Benn, an eastern Asian pondweed. Its discovery in Britain encourages a reassessment of plant macrofossil assemblages from western Europe, which may lead to a consideration of the relationship between the Late Pleistocene vegetation of Europe and eastern Asia.Bioarchaeolog

Upper Pleistocene stratigraphy at the Medininkai site, eastern Lithuania: a continuous record of the Eemian-Weichselian sequence

Eemian-Weichselian sequences, located outside the maximum limit of the Late Weichselian ice sheet, provide excellent opportunities for the discovery of continuous sedimentary records encompassing the whole Last Interglacial/Glacial cycle. Such a sequence is recorded in a borehole (117P) through the succession in a small kettlehole lake located at Medininkai, eastern Lithuania. The succession consists of peat, gyttja and silt deposited on top of a Saalian till. Pollen and plant macrofossil analysis, lithological analysis, U/Th dating and mineral magnetic measurements on the sediments have allowed 19 lithostratigraphic units and 16 local pollen assemblage zones (LPAZ) to be identified. The palaeocarpological record reveals a clear transition from the Saalian Glacial to the Weichselian stadial and interstadial phases. The mineral magnetic parameters suggest a good correlation between the concentration of magnetic minerals and stadial and interstadial periods. The Merkine (Eemian) Interglacial and two Early Weichselian Interstadials, Jonionys 1 (Brorup) and Jonionys 2 (Odderade), separated by cryomers, are identified. Intervals interpreted as analogous to the Middle Weichselian Denekamp and Hengelo interstadials are also recognized on the basis of pollen assemblages. The results show alternating periglacial and interstadial palaeoenvironments in Lithuania during the Early and Middle Weichselian and are of importance for Late Pleistocene palaeoenvironmental reconstruction of the Baltic area as a whole