38 research outputs found
High-performance adaptive neurofuzzy classifier with a parametric tuning
The article is devoted to research and development of adaptive algorithms for neuro-fuzzy inference when solving multicriteria problems connected with analysis of expert (foresight) data to identify technological breakthroughs and strategic perspectives of scientific, technological and innovative development. The article describes the optimized structuralfunctional scheme of the high-performance adaptive neuro-fuzzy classifier with a logical output, which has such specific features as a block of decision tree-based fuzzy rules and a hybrid algorithm for neural network adaptation of parameters based on the error back-propagation to the root of the decision tree
Adaptive neuro-fuzzy classifier for evaluating the technology effectiveness based on the modified Wang and Mendel fuzzy neural production MIMO-network
The paper describes practical results gained during synthesis of the classification model for estimating technology effectiveness when solving multi-criteria problems of expert data analysis (Foresight) aimed to identify technological breakthroughs and strategic perspectives of scientific, technological and innovative developmen
Adaptive fuzzy neural production network with MIMO-structure for the evaluation of technology efficiency
The paper presents an example of modeling the algorithm operation. The paper analyses the modified Wang and Mendel MIMO-architecture of the adaptive fuzzy neural production network with a logical conclusion. It is distinguished by the automatic generation of a set of fuzzy rules based on a fuzzy decision tree and a hybrid algorithm for parameter adaptation by the neural network (centers, widths of membership functions, and conclusions) starting from the leaf nodes to the root nodes of the tree
Neuro-fuzzy methods in cognitive systems of monitoring and forecasting of scientific and technological development of the country
On the basis of many national and international research a neural network model of the trajectory of and techno-economic development, which allows to calculate the level and rate of fuel and energy is developed and the method of evaluating the effectiveness of technological innovation projects on a range of qualitative and quantitative parameters based on the construction of the neuro-fuzzy solution tree is proposed. The developed model, in addition to the promising project choosing, explains the decision making process in an understandable way, in the structure of the neuro-diagnostic decision rules “If ... then.” Thus, this technique allows to determine the significance of the indicators (trends) of the formation of new technological cycles and to identify the reference parameters of the social dimension of the economy. Data received as a result of the intellectual analysis can be used by experts to assess the efficiency of the automated calculation of the effectiveness of technology projects in order to predict the scientific and technological development of the country and make necessary recommendations to the political and socio-economic spheres. Research results can be used both by private and public companies and organizations. This will help to assess and predict future changes, give proper recommendations to scientific institutions in key areas: such as security and counter-terrorism; living systems; nanosystem and materials Industry, information and telecommunication systems, advanced weapons, military and special equipment, management natural resources, transport, aviation and space systems, energy and energy efficiency
Vertical Field Effect Transistor based on Graphene-WS2 Heterostructures for flexible and transparent electronics
The celebrated electronic properties of graphene have opened way for
materials just one-atom-thick to be used in the post-silicon electronic era. An
important milestone was the creation of heterostructures based on graphene and
other two-dimensional (2D) crystals, which can be assembled in 3D stacks with
atomic layer precision. These layered structures have already led to a range of
fascinating physical phenomena, and also have been used in demonstrating a
prototype field effect tunnelling transistor - a candidate for post-CMOS
technology. The range of possible materials which could be incorporated into
such stacks is very large. Indeed, there are many other materials where layers
are linked by weak van der Waals forces, which can be exfoliated and combined
together to create novel highly-tailored heterostructures. Here we describe a
new generation of field effect vertical tunnelling transistors where 2D
tungsten disulphide serves as an atomically thin barrier between two layers of
either mechanically exfoliated or CVD-grown graphene. Our devices have
unprecedented current modulation exceeding one million at room temperature and
can also operate on transparent and flexible substrates
Atomically thin boron nitride: a tunnelling barrier for graphene devices
We investigate the electronic properties of heterostructures based on
ultrathin hexagonal boron nitride (h-BN) crystalline layers sandwiched between
two layers of graphene as well as other conducting materials (graphite, gold).
The tunnel conductance depends exponentially on the number of h-BN atomic
layers, down to a monolayer thickness. Exponential behaviour of I-V
characteristics for graphene/BN/graphene and graphite/BN/graphite devices is
determined mainly by the changes in the density of states with bias voltage in
the electrodes. Conductive atomic force microscopy scans across h-BN terraces
of different thickness reveal a high level of uniformity in the tunnel current.
Our results demonstrate that atomically thin h-BN acts as a defect-free
dielectric with a high breakdown field; it offers great potential for
applications in tunnel devices and in field-effect transistors with a high
carrier density in the conducting channel.Comment: 7 pages, 5 figure
Non-minimally Coupled Cosmological Models with the Higgs-like Potentials and Negative Cosmological Constant
We study dynamics of non-minimally coupled scalar field cosmological models
with Higgs-like potentials and a negative cosmological constant. In these
models the inflationary stage of the Universe evolution changes into a
quasi-cyclic stage of the Universe evolution with oscillation behaviour of the
Hubble parameter from positive to negative values. Depending on the initial
conditions the Hubble parameter can perform either one or several cycles before
to become negative forever.Comment: 22 pages, 6 figures, v4:Section 2 expanded, references added,
accepted for publication in Class. Quant. Gra
How close can one approach the Dirac point in graphene experimentally?
The above question is frequently asked by theorists who are interested in
graphene as a model system, especially in context of relativistic quantum
physics. We offer an experimental answer by describing electron transport in
suspended devices with carrier mobilities of several 10^6 cm^2V^-1s^-1 and with
the onset of Landau quantization occurring in fields below 5 mT. The observed
charge inhomogeneity is as low as \approx10^8 cm^-2, allowing a neutral state
with a few charge carriers per entire micron-scale device. Above liquid helium
temperatures, the electronic properties of such devices are intrinsic, being
governed by thermal excitations only. This yields that the Dirac point can be
approached within 1 meV, a limit currently set by the remaining charge
inhomogeneity. No sign of an insulating state is observed down to 1 K, which
establishes the upper limit on a possible bandgap
Micrometer-scale ballistic transport in encapsulated graphene at room temperature
Devices made from graphene encapsulated in hexagonal boron-nitride exhibit
pronounced negative bend resistance and an anomalous Hall effect, which are a
direct consequence of room-temperature ballistic transport on a micrometer
scale for a wide range of carrier concentrations. The encapsulation makes
graphene practically insusceptible to the ambient atmosphere and,
simultaneously, allows the use of boron nitride as an ultrathin top gate
dielectric