38 research outputs found
Decrease of time of model synthesis in intellectual monitoring systems
The article investigates modern intellectual monitoring systems (IMS), which are able to predict the consequences of the adopted control decisions of decision support systems (DSS), thanks to the modeling of the characteristics of monitored objects. The drawbacks of existing implementations of IMS show when working in crisis monitoring. Since crisis monitoring imposes a number of restrictions on the speed of DSS and the high probability of failure of the trained IMS models, the use of existing implementations of IMS is problematic. The reasons of the existence of these shortcomings, and the algorithms with which it is connected lies in existing methodology. The paper investigates advantages and disadvantages of existing methods for the formation of inter-level relations in the IMS. A particular attention is paid to the method of classification of input data arrays (IDA) according to their characteristics, to the corresponding class of model synthesis algorithm (MSA). This paper proposes to improve the well-known method of classifying MIA by using unique adaptive classifiers for each of the MSA class.У статті досліджено сучасні моніторингові інтелектуальні системи (МІС), які здатні прогнозувати наслідки прийнятих керуючих рішень систем підтримки прийняття рішень (СППР) завдяки моделюванню характеристик об’єктів моніторингу. Продемонстровано недоліки існуючих реалізацій МІС при роботі в умовах кризового моніторингу. Так як кризовий моніторинг накладає ряд обмежень на швидкість роботи СППР та велику вірогідність виходу навчених моделей МІС із строю, то використання існуючих реалізацій МІС є проблематичним. Досліджено причини існування даних недоліків та алгоритми, з якими це пов’язано. Досліджено переваги та недоліки існуючих методів формування міжрівневих зв’язків у МІС. Особливу увагу звернено на метод класифікації масивів вхідних даних (МВД) за їх характеристиками до відповідного класу алгоритмів синтезу моделей (АСМ). Запропоновано вдосконалити відомий метод класифікації масивів вхідних даних за допомогою використання унікальних адаптивних класифікаторів для кожного із класів алгоритмів синтезу моделей із списку реалізованих у системі.В статье исследованы современные мониторинговые интеллектуальные системы (МИС), которые способны прогнозировать последствия принимаемых управляющих решений систем поддержки принятия решений (СППР) благодаря моделированию характеристик объектов мониторинга. Продемонстрированы недостатки существующих реализаций МИС при работе в условиях кризисного мониторинга. Так как кризисный мониторинг накладывает ряд ограничений на скорость работы СППР и большую вероятность выхода обученных моделей МИС из строя, то использование существующих реализаций МИС является проблематичным. Исследованы причины существования данных недостатков и алгоритмы, с которыми это связано. Исследованы преимущества и недостатки существующих методов формирования межуровневых связей в МИС. Особое внимание обращено на метод классификации массивов входных данных (МВД) по их характеристикам к соответствующему классу алгоритмов синтеза моделей (АСМ). Предложено усовершенствовать известный метод классификации МВД посредством использования уникальных адаптивных классификаторов для каждого из классов АСМ
Effect of the visible light irradiation of fullerene containing composites on the ros generation and the viability of tumor cells
Aim: To study the effect of fullerene-containing composites, irradiated by visible light, on the radical oxygen species (ROS) generation in thymocytes, ascitic cells from Erlich’s tumor and leukemia cells L1210; to investigate viability of these cells in the presence of fullerene-containing composites under irradiation conditions. Materials and Methods: The viability of cells was evaluated by staining with 0.4% solution of the trypan blue; ROS were detected with the use of electron paramagnetic resonance (EPR) spectroscopy and spin traps; solutions of fullerene-containing composites were irradiated with mercury-vapor lamp. Results: We demonstrated that under irradiation conditions fullerene-containing composites increase the rate of ROS generation and decrease the number of viable tumor cells. Conclusions: The obtained data allow to consider the fullerene-containing composites as potential agents for photodynamic therapy.Цель: изучить влияние фуллеренсодержащих композитов, облученных видимым светом, на генерирование радикальных
форм кислорода (РФК) в клетках тимоцитов, асцитного рака Эрлиха и лейкоза L1210. Исследовать жизнеспособность
этих клеток в присутствии облученных фуллеренсодержащих композитов. Методы: жизнеспособность клеток определяли с
использованием 0,4 % раствора трипанового синего; РФК регистрировали методом ЭПР- спектроскопии и спиновых ловушек;
облучение водных раcтворов фуллеренсодержащих композитов в видимом диапазоне осуществляли с помощью ртутной
лампы. Результаты: показано, что фуллеренсодержащие композиты при облучении повышают скорость генерирования РФК
и уменьшают количество жизнеспособных опухолевых клеток. Выводы: полученные результаты позволяют рассматривать
фуллеренсодержащие композиты как потенциальные препараты для фотодинамической терапии
Effect of intersubband scattering on weak localization in 2D systems
The theory of weak localization is generalized for multilevel 2D systems
taking into account intersubband scattering. It is shown that weak intersubband
scattering which is negligible in a classical transport, affects strongly the
weak-localization correction to conductivity. The anomalous magnetoresistance
is calculated in the whole range of classically low magnetic fields. This
correction to conductivity is shown to depend strongly on the ratios of
occupied level concentrations. It is demonstrated that at relatively low
population of the excited subband, it is necessary to use the present theory
because the high-field limit asimptotics is shown to be achieved only in
classical magnetic fields.Comment: 18 pages, 4 figures. Accepted to Phys. Rev. B 6
Theory and computation of covariant Lyapunov vectors
Lyapunov exponents are well-known characteristic numbers that describe growth
rates of perturbations applied to a trajectory of a dynamical system in
different state space directions. Covariant (or characteristic) Lyapunov
vectors indicate these directions. Though the concept of these vectors has been
known for a long time, they became practically computable only recently due to
algorithms suggested by Ginelli et al. [Phys. Rev. Lett. 99, 2007, 130601] and
by Wolfe and Samelson [Tellus 59A, 2007, 355]. In view of the great interest in
covariant Lyapunov vectors and their wide range of potential applications, in
this article we summarize the available information related to Lyapunov vectors
and provide a detailed explanation of both the theoretical basics and numerical
algorithms. We introduce the notion of adjoint covariant Lyapunov vectors. The
angles between these vectors and the original covariant vectors are
norm-independent and can be considered as characteristic numbers. Moreover, we
present and study in detail an improved approach for computing covariant
Lyapunov vectors. Also we describe, how one can test for hyperbolicity of
chaotic dynamics without explicitly computing covariant vectors.Comment: 21 pages, 5 figure
Signatures of the slow solar wind streams from active regions in the inner corona
Some of local sources of the slow solar wind can be associated with
spectroscopically detected plasma outflows at edges of active regions
accompanied with specific signatures in the inner corona. The EUV telescopes
(e.g. SPIRIT/CORONAS-F, TESIS/CORONAS-Photon and SWAP/PROBA2) sometimes
observed extended ray-like structures seen at the limb above active regions in
1MK iron emission lines and described as "coronal rays". To verify the
relationship between coronal rays and plasma outflows, we analyze an isolated
active region (AR) adjacent to small coronal hole (CH) observed by different
EUV instruments in the end of July - beginning of August 2009. On August 1 EIS
revealed in the AR two compact outflows with the Doppler velocities V =10-30
km/s accompanied with fan loops diverging from their regions. At the limb the
ARCH interface region produced coronal rays observed by EUVI/STEREO-A on July
31 as well as by TESIS on August 7. The rays were co-aligned with open magnetic
field lines expanded to the streamer stalks. Using the DEM analysis, it was
found that the fan loops diverged from the outflow regions had the dominant
temperature of ~1 MK, which is similar to that of the outgoing plasma streams.
Parameters of the solar wind measured by STEREO-B, ACE, WIND, STEREO-A were
conformed with identification of the ARCH as a source region at the
Wang-Sheeley-Arge map of derived coronal holes for CR 2086. The results of the
study support the suggestion that coronal rays can represent signatures of
outflows from ARs propagating in the inner corona along open field lines into
the heliosphere.Comment: Accepted for publication in Solar Physics; 31 Pages; 13 Figure
The Science of Sungrazers, Sunskirters, and Other Near-Sun Comets
This review addresses our current understanding of comets that venture close to the Sun, and are hence exposed to much more extreme conditions than comets that are typically studied from Earth. The extreme solar heating and plasma environments that these objects encounter change many aspects of their behaviour, thus yielding valuable information on both the comets themselves that complements other data we have on primitive solar system bodies, as well as on the near-solar environment which they traverse. We propose clear definitions for these comets: We use the term near-Sun comets to encompass all objects that pass sunward of the perihelion distance of planet Mercury (0.307 AU). Sunskirters are defined as objects that pass within 33 solar radii of the Sun’s centre, equal to half of Mercury’s perihelion distance, and the commonly-used phrase sungrazers to be objects that reach perihelion within 3.45 solar radii, i.e. the fluid Roche limit. Finally, comets with orbits that intersect the solar photosphere are termed sundivers. We summarize past studies of these objects, as well as the instruments and facilities used to study them, including space-based platforms that have led to a recent revolution in the quantity and quality of relevant observations. Relevant comet populations are described, including the Kreutz, Marsden, Kracht, and Meyer groups, near-Sun asteroids, and a brief discussion of their origins. The importance of light curves and the clues they provide on cometary composition are emphasized, together with what information has been gleaned about nucleus parameters, including the sizes and masses of objects and their families, and their tensile strengths. The physical processes occurring at these objects are considered in some detail, including the disruption of nuclei, sublimation, and ionisation, and we consider the mass, momentum, and energy loss of comets in the corona and those that venture to lower altitudes. The different components of comae and tails are described, including dust, neutral and ionised gases, their chemical reactions, and their contributions to the near-Sun environment. Comet-solar wind interactions are discussed, including the use of comets as probes of solar wind and coronal conditions in their vicinities. We address the relevance of work on comets near the Sun to similar objects orbiting other stars, and conclude with a discussion of future directions for the field and the planned ground- and space-based facilities that will allow us to address those science topics
Dwell-time distributions in quantum mechanics
Some fundamental and formal aspects of the quantum dwell time are reviewed,
examples for free motion and scattering off a potential barrier are provided,
as well as extensions of the concept. We also examine the connection between
the dwell time of a quantum particle in a region of space and flux-flux
correlations at the boundaries, as well as operational approaches and
approximations to measure the flux-flux correlation function and thus the
second moment of the dwell time, which is shown to be characteristically
quantum, and larger than the corresponding classical moment even for freely
moving particles.Comment: To appear in "Time in Quantum Mechanics, Vol. 2", Springer 2009, ed.
by J. G. Muga, A. Ruschhaupt and A. del Camp