152 research outputs found
Multispectral optoelectronic device for controlling an autonomous mobile platform
The paper substantiates the use of multispectral optoelectronic sensors intended to solve the problem of improving the positioning accuracy of autonomous mobile platforms. A mathematical model of the developed device operation has been suggested in the paper. Its distinctive feature is the cooperative processing of signals obtained from sensors operating in ultraviolet, visible, and infrared ranges and lidar. It reduces the computational complexity of detecting dynamic and stationary objects within the field of view of the device by processing data on the diffuse reflectivity of materials. The paper presents the functional organization of a multispectral optoelectronic device that makes it possible to detect and classify working scene objects with less time spending as compared to analogs. In the course of experimental research, the validity of the mathematical model was evaluated and there were obtained empirical data by means of the proposed hardware and software test stand. The accuracy evaluation of the detected object, at a distance of up to 100m inclusive, is within 0.95. At a distance of more than 100 m, it decreases. This is due to the operating range of a lidar. Error in determining spatial coordinates is of exponential character and it also increases sharply at a distance close to 100 m
Calculation of optimal parameters for aircraft recognition on remote sensing imagery by contour analysis
In this paper, we describe the experimental results of aircraft recognition on optical remote sensing imagery using the theory of contour analysis. We propose the new technique to calculate optimal values of the contour’s items quantity and the classification threshold through measuring within- and between-class distances for all possible training set instances combinations with the following detecting and minimizing the type I and II errors. We discuss the construction of contours’ similarity measures combining the principles of finding the most appropriate reference instance and calculating the average value for the whole class. It is shown that the proposed parameters' calculation technique and the similarity function provides training on compact non-uniform datasets and the further of an aircrafts' recognition on images of lower spatial resolution
Locating current sheets in the solar corona
Current sheets are essential for energy dissipation in the solar corona, in
particular by enabling magnetic reconnection. Unfortunately, sufficiently thin
current sheets cannot be resolved observationally and the theory of their
formation is an unresolved issue as well. We consider two predictors of coronal
current concentrations, both based on geometrical or even topological
properties of a force free coronal magnetic field. First, there are
separatrices related to magnetic nulls. Through separatrices the magnetic
connectivity changes discontinuously. Coronal magnetic nulls are, however, very
rare. At second, inspired by the concept of generalized magnetic reconnection
without nulls, quasi-separatrix layers (QSL) were suggested. Through QSL the
magnetic connectivity changes continuously, though strongly. The strength of
the connectivity change can be quantified by measuring the squashing of the
flux tubes which connect the magnetically conjugated photospheres.
We verify the QSL and separatrix concepts by comparing the sites of magnetic
nulls and enhanced squashing with the location of current concentrations in the
corona. Due to the known difficulties of their direct observation we simulated
the coronal current sheets by numerically calculating the response of the
corona to energy input from the photosphere heating a simultaneously observed
EUV Bright Point. We did not find coronal current sheets not at the
separatrices but at several QSL locations. The reason is that although the
geometrical properties of force free extrapolated magnetic fields can indeed,
hint at possible current concentrations, a necessary condition for current
sheet formation is the local energy input into the corona
Особенности стратегического управления малым предприятием
The feature of strategic management at the small enterprise consists in the contents of business strategy. From set of possible (probable) business strategy the small enterprises for the essence successfully can adhere only to adaptive strategy. The adaptive strategy should develop on the basis of association of industrial operations in uniform business-processes. Though in modern researches such concepts are widely used, as the reorganization and re-structuring, but, in opinion of the authors, orientation of processes of transformations to structures of the enterprise separate operations and tasks, instead of on business-process is traditional, most widespread mistake.Особенность стратегического управления на малом предприятии заключается в содержании самих деловых стратегий. Из множества возможных деловых стратегий малые предприятия по своей сущности успешно могут придерживаться только адаптивных стратегий. Адаптивные стратегии должны развиваться на основе объединения производственных операций в единые бизнес-процессы. Хотя в современных исследованиях широко используются такие понятия, как реорганизация и реструктуризация, но, по мнению авторов, ориентация процессов преобразований на структуры предприятия, отдельные операции и задачи, а не на бизнес-процесс является традиционной, наиболее распространенной ошибкой
Этапы управления малым предприятием
Proceeding from practical experience of management complemented by study of foreign and domestic experience, the authors offer to improve a control system, having allocated three basic stages of management of the small enterprise. The offered model of management will help to formalize process of management of the small enterprise, and, hence to raise(increase) efficiency of activity of the enterprise.Исходя из зарубежного и отечественного практического опыта управления авторы предлагают совершенствовать систему управления, выделив три этапа управления малым предприятием. Предлагаемая модель управления поможет формализовать процесс управления малым предприятием, а следовательно, повысить эффективность деятельности предприятия
Is null-point reconnection important for solar flux emergence?
The role of null-point reconnection in a 3D numerical MHD model of solar
emerging flux is investigated. The model consists of a twisted magnetic flux
tube rising through a stratified convection zone and atmosphere to interact and
reconnect with a horizontal overlying magnetic field in the atmosphere. Null
points appear as the reconnection begins and persist throughout the rest of the
emergence, where they can be found mostly in the model photosphere and
transition region, forming two loose clusters on either side of the emerging
flux tube. Up to 26 nulls are present at any one time, and tracking in time
shows that there is a total of 305 overall, despite the initial simplicity of
the magnetic field configuration. We find evidence for the reality of the nulls
in terms of their methods of creation and destruction, their balance of signs,
their long lifetimes, and their geometrical stability. We then show that due to
the low parallel electric fields associated with the nulls, null-point
reconnection is not the main type of magnetic reconnection involved in the
interaction of the newly emerged flux with the overlying field. However, the
large number of nulls implies that the topological structure of the magnetic
field must be very complex and the importance of reconnection along separators
or separatrix surfaces for flux emergence cannot be ruled out.Comment: 26 pages, 12 figures. Added one referenc
Why are flare ribbons associated with the spines of magnetic null points generically elongated?
Coronal magnetic null points exist in abundance as demonstrated by
extrapolations of the coronal field, and have been inferred to be important for
a broad range of energetic events. These null points and their associated
separatrix and spine field lines represent discontinuities of the field line
mapping, making them preferential locations for reconnection. This field line
mapping also exhibits strong gradients adjacent to the separatrix (fan) and
spine field lines, that can be analysed using the `squashing factor', . In
this paper we make a detailed analysis of the distribution of in the
presence of magnetic nulls. While is formally infinite on both the spine
and fan of the null, the decay of away from these structures is shown in
general to depend strongly on the null-point structure. For the generic case of
a non-radially-symmetric null, decays most slowly away from the spine/fan
in the direction in which increases most slowly. In particular,
this demonstrates that the extended, elliptical high- halo around the spine
footpoints observed by Masson et al. (Astrophys. J., 700, 559, 2009) is a
generic feature. This extension of the halos around the spine/fan
footpoints is important for diagnosing the regions of the photosphere that are
magnetically connected to any current layer that forms at the null. In light of
this, we discuss how our results can be used to interpret the geometry of
observed flare ribbons in `circular ribbon flares', in which typically a
coronal null is implicated. We conclude that both the physics in the vicinity
of the null and how this is related to the extension of away from the
spine/fan can be used in tandem to understand observational signatures of
reconnection at coronal null points.Comment: Pre-print version of article accepted for publication in Solar
Physic
Study of KS KL Coupled Decays and KL -Be Interactions with the CMD-2 Detector at VEPP-2M Collider
The integrated luminosity about 4000 inverse nanobarn of around phi meson
mass ( 5 millions of phi mesons) has been collected with the CMD-2 detector at
the VEPP-2M collider. A latest analysis of the KS KL coupled decays based on 30
% of available data is presented in this paper.
The KS KL pairs from phi meson decays were reconstructed in the drift chamber
when both kaons decayed into two charged particles. From a sample of 1423
coupled decays a selection of candidates to the CP violating KL into pi+ pi-
decay was performed. CP violating decays were not identified because of the
domination of events with a KL regenerating at the Be beam pipe into KS and a
background from KL semileptonic decays.
The regeneration cross section of 110 MeV/c KL mesons was found to be 53 +-
17 mb in agreement with theoretical expectations. The angular distribution of
KS mesons after regeneration and the total cross section of KL for Be have been
measured.Comment: 14 pages, 8 figure
Observation of semileptonic decays with CMD-2 detector
The decay has been observed by the CMD-2 detector at
the e^+e^- collider VEPP-2M at Novosibirsk. Of 6 million produced
pairs, events of the decay were selected. The
corresponding branching ratio is . This result is consistent with the evaluation of from the semileptonic rate and lifetime
assuming .Comment: 7 pages, 6 figures, LaTex2e. Submitted to Phys.Lett.
Measurement of omega meson parameters in pi^+pi^-pi^0 decay mode with CMD-2
About 11 200 e^+e^- -> omega -> pi^+pi^-pi^0 events selected in the center of
mass energy range from 760 to 810 MeV were used for the measurement of the
\omega meson parameters. The following results have been obtained: sigma
_{0}=(1457 \pm 23 \pm 19)nb, m_{\omega}=(782.71 \pm 0.07 \pm 0.04) MeV/c^{2},
\Gamma_{\omega}=(8.68 \pm 0.23 \pm 0.10) MeV,
\Gamma_{e^+e^-}\cdot Br (\omega -> pi^+pi^-pi^0)=
(0.528 \pm 0.012 \pm 0.007) \cdot 10^{-3} MeV.Comment: 8 pages, 4 figure
- …