54 research outputs found
Phytosociological study of the forest vegetation of Kyiv urban area (Ukraine)
The current study presents the floristic-sociological classification of the forest vegetation of the Kyiv urban area. We identified 21 associations and variants belonging to 7 classes, 8 orders and 10 alliances of the forest vegetation. Some of them were described with new names, particularly, in the classes of Alno glutinosae-Populetea albae (Aristolochio clematitis-Populetum nigrae ass. nov. hoc loco), Robinietea (Galio aparines-Aceretum negundi ass. nov. hoc loco), Galio-Urticetea (Lapsano communis-Urticetum dioicae ass. nov. hoc loco), Quercetea robori-petraeae (Poo nemoralis-Quercetum roboris ass. nov. hoc loco), Vaccinio-Piceetea (Luzulo pilosae-Pinetum sylvestris ass. nov. hoc loco, Calamagrostio epigeii-Pinetum sylvestris ass. nov. hoc loco). Vegetation classification was conducted using the original DRSA algorithm (Distance-Ranked Sorting Algorithm) based on the k-nearest neighbors clustering approach. The phytocoenons were analyzed using ordination, phytoindication, and by inter-cluster similarity evaluation and described by traits of synmorphology, ecological specificity, distribution data, phytosociological spectrum, and syntaxonomical relations
On the Influence of Hand Dynamics on Motion Planning of Reaching Movements in Haptic Environments
The paper presents an analysis of human reaching movements in the manipulation of flexible objects. Two models, the minimum hand jerk and the minimum driving hand forcechange, are used for modelling and verification of experimental data. The data are collected with the haptic system supporting dynamic simulation of the flexible object in real time. We describe some initial experimental results and analyze the applicability of the models. It is found that even for short-term movements human motion planning strategy can depend on arm inertia and configuration. This conclusion is based on the experimental evidence of the multi-phased hand velocity profiles that can be well captured by the minimum driving hand force-change criterion. To support the latest observation, an experiment with reinforcement learning was conducted
Shift in the structure of Lasius flavus (Hymenoptera, Formicidae) nest complexes under the influence of anthropogenic factors
The structure of five Lasius flavus Fabricius, 1781 (yellow meadow ant) nest complexes with
33 to 211 nest mounds exposed to the anthropogenic impact of varying intensity was studied
in 2001 and 2014 from four locations in Crimea. The study areas can be arranged in order of
increasing intensity of anthropogenic impact as follows: the Chatyr-Dag Mountain (no impact,
two nest complexes), arboretum near Simferopol city (low-intensity impact, moderate grazing,
one nest complex), the outskirts of Kurtsy village (high-intensity impact, intensive grazing, ne
nest complex), and Gagarinsky Park (critical level of intensity, draining, one nest complex). In
2001, mound measurements were taken from all nest complexes, divided into squares of 20 ×
20 m. In 2014, mound measurements were taken from three out of five locations, namely the
Chatyr-Dag Mountain (one nest complex), Kurtsy village, and Gagarinsky Park). In 2014, the
nest complex in Gagarinsky Park was found to no longer exist. Other nest complexes
underwent significant changes. Small nest mounds either disappeared or grew in size. The total
nest volume did not change significantly or slightly increased. Therefore, this study concluded
that grazing did not affect the ability of nest complexes to grow. The lowering of the
groundwater table was found to be a critical factor. Nest complexes on the Chatyr-Dag plateau
turned out to be 100 years of age, and other nest complexes were at the age of 40 to 80 years
Optimality Principles and Motion Planning of Human-Like Reaching Movements
The paper deals with modeling of human-like reaching movements. Several issues are under study. First, we consider a model of unconstrained reaching movements that corresponds to the minimization of control effort. It is shown that this model can be represented by the wellknown Beta function. The representation can be used for the construction of fractional order models and also for modeling of asymmetric velocity proï¬les. Next, we address the formation of boundary conditions in a natural way. From the mathematical point of view, the structure of the optimal solution is deï¬ned not only by the form of the optimality criterion but also by the boundary conditions of the optimization task. The natural boundary conditions, deï¬ned in this part of the paper, can also be used in modeling asymmetric velocity proï¬les. Finally, addressing the modeling of reaching movements with bounded control actions, we consider the minimum time formulation of the optimization problem and (for the n-th order integrator) ï¬nd its analytical solution
Analysis of propagation of orthogonally polarized supermode in straight and curved multicore microstructured fibres, Journal of Telecommunications and Information Technology, 2007, nr 4
We analyze the dependence of radiation loss, effective indices and difference of the effective indices of the two modes with similar field distribution propagating in dual-core microstructured fibres as well as their polarization behavior on fibre parameters (air hole diameter, hole separation, distance between guiding cores) and fibre bending. Optimization of the parameters of such fibres using as vector bend sensors is considered
Photonic crystal fibre characterisation with the method of lines, Journal of Telecommunications and Information Technology, 2004, nr 1
Photonic crystal fibres are longitudinally uniform fibres in which in lateral directions periodic refractive index changes occur. Two basically different light guiding mechanisms occur in crystal fibres: index guiding and bandgap guiding. In the paper different modelling methods have been evaluated when applied to photonic crystal fibres. In particular, the method of lines has been shown to be effective and reliable for both classes of photonic crystal fibres. High accuracy results for optical field distribution and dispersion characteristics in a photonic crystal fibre have been achieved with the method of lines
Optimizing the Structure of Vector Bend and Strain Sensor on the Base of Three-Core Microstructured Fiber, Journal of Telecommunications and Information Technology, 2012, nr 4
In the paper the optical sensor allowing measuring a direction, values and localization of bends and stresses in building structures is described. The sensitive element of the sensor is the microstructured fiber with three cores. The use of three-core fiber makes it possible to define the direction of deformation. Distribution of mode fields in fiber cores depending on fiber structure and bend value and direction is analyzed. The optimization of the sensitive element parameters depending on the application is proposed
- …