26 research outputs found
Optimization of Enzymatic Logic Gates and Networks for Noise Reduction and Stability
Biochemical computing attempts to process information with biomolecules and
biological objects. In this work we review our results on analysis and
optimization of single biochemical logic gates based on enzymatic reactions,
and a network of three gates, for reduction of the "analog" noise buildup. For
a single gate, optimization is achieved by analyzing the enzymatic reactions
within a framework of kinetic equations. We demonstrate that using
co-substrates with much smaller affinities than the primary substrate, a
negligible increase in the noise output from the logic gate is obtained as
compared to the input noise. A network of enzymatic gates is analyzed by
varying selective inputs and fitting standardized few-parameters response
functions assumed for each gate. This allows probing of the individual gate
quality but primarily yields information on the relative contribution of the
gates to noise amplification. The derived information is then used to modify
experimental single gate and network systems to operate them in a regime of
reduced analog noise amplification.Comment: 7 pages in PD
Enzymatic Logic Gates with Noise-Reducing Sigmoid Response
Biochemical computing is an emerging field of unconventional computing that
attempts to process information with biomolecules and biological objects using
digital logic. In this work we survey filtering in general, in biochemical
computing, and summarize the experimental realization of an AND logic gate with
sigmoid response in one of the inputs. The logic gate is realized with
electrode-immobilized glucose-6-phosphate dehydrogenase enzyme that catalyzes a
reaction corresponding to the Boolean AND functions. A kinetic model is also
developed and used to evaluate the extent to which the performance of the
experimentally realized logic gate is close to optimal.Comment: 14 pages, 2 figures, PD
Spin configurations in circular and rectangular vertical quantum dots in a magnetic field: Three-dimensional self-consistent simulation
The magnetic field dependence of the electronic properties of \textit{real}
single vertical quantum dots in circular and rectangular mesas is investigated
within a full three-dimensional multiscale self-consistent approach without any
{\it \'a priori} assumptions about the shape and strength of the confinement
potential. The calculated zero field electron addition energies are in good
agreement with available experimental data for both mesa geometries. Charging
diagrams in a magnetic field for number of electrons up to five are also
computed. Consistent with the experimental data, we found that the charging
curves for the rectangular mesa dot in a magnetic field are flatter and exhibit
less features than for a circular mesa dot. Evolution of the singlet-triplet
energy separation in the two electron system for both dot geometries in
magnetic field was also investigated. In the limit of large field, beyond the
singlet-triplet transition, the singlet-triplet energy difference continues to
become more negative in a circular mesa dot without any saturation within the
range of considered magnetic fields whilst it is predicted to asymptotically
approach zero for the rectangular mesa dot. This different behavior is
attributed to the symmetry "breaking" that occurs in the singlet wave-functions
in the rectangular mesa dot but not in the circular one.Comment: 12 pages, 8 gifure
Enzymatic AND Logic Gates Operated Under Conditions Characteristic of Biomedical Applications
Experimental and theoretical analyses of the lactate dehydrogenase and
glutathione reductase based enzymatic AND logic gates in which the enzymes and
their substrates serve as logic inputs are performed. These two systems are
examples of the novel, previously unexplored, class of biochemical logic gates
that illustrate potential biomedical applications of biochemical logic. They
are characterized by input concentrations at logic 0 and 1 states corresponding
to normal and abnormal physiological conditions. Our analysis shows that the
logic gates under investigation have similar noise characteristics. Both
significantly amplify random noise present in inputs, however we establish that
for realistic widths of the input noise distributions, it is still possible to
differentiate between the logic 0 and 1 states of the output. This indicates
that reliable detection of abnormal biomedical conditions is indeed possible
with such enzyme-logic systems.Comment: PDF, 29 page
Enzymatic AND-Gate Based on Electrode-Immobilized Glucose-6-Phosphate Dehydrogenase: Towards Digital Biosensors and Biochemical Logic Systems with Low Noise
Electrode-immobilized glucose-6-phosphate dehydrogenase is used to catalyze
an enzymatic reaction which carries out the AND logic gate. This logic function
is considered here in the context of biocatalytic processes utilized for the
biocomputing applications for "digital" (threshold) sensing/actuation. We
outline the response functions desirable for such applications and report the
first experimental realization of a sigmoid-shape response in one of the
inputs. A kinetic model is developed and utilized to evaluate the extent to
which the experimentally realized gate is close to optimal
Green roofs in Saint Petersburg
The aim of this work was to investigate Russian and foreign projects of green roofs, evaluate the possibility of building a green roof on the building Gidrokorpus and write recommendations for its installation and maintenance.
Construction of green roofs is becoming now one of the fastest growing areas of landscape architecture and is becoming increasingly popular in St. Petersburg. Considering the insufficient number of domestic works of green roofs in local climatic conditions, a number of environmental advantages of extensive green roofs with different types of vegetation in conditions of St. Petersburg was investigated. Also the possibility of building a green roof on the Gidrokorpus was evaluated and recommendations for its installation were developed.
Ekaterina Zalata was responsible for Chapter 2 (Green roofs now and in the past) and Chapter 4 (Green roof buildings in Saint Petersburg). Dmitriy Melnikov was responsible for Chapter 3 (Green roofs in construction). Chapter 5 (Construction solutions for the roof system of Gidrocorpus) was written by both Ekaterina and Dmitriy.
As the result a construction decision for the roof of Gidrocorpus was provided to the company Delta-t
К РУССКОЯЗЫЧНОЙ НАД-ЛИТЕРАТУРЕ: СОЗДАВАЯ СУБЪЕКТИВНОСТИ, ПРОСТРАНСТВА И ТЕМПОРАЛЬНОСТИ В ПОСТСОВЕТСКОЙ КАЗАХСТАНСКОЙ РУССКОЯЗЫЧНОЙ ЛИТЕРАТУРЕ
This thesis is devoted to the analysis of literary works by a number of the leading
post-Soviet Russophone Kazakhstani writers: Anuar Duisenbinov, Bakhyt Kairbekov,
Diusenbek Nakipov, Nikolai Verёvochkin, Il’ia Odegov and Iurii Serebrianskii.
Kazakhstan is a country where Russian literature has been developing quite successfully
since the collapse of the USSR. There has been a transformation of writing in Russian in
Kazakhstan since the country’s independence – with the rise of the new generation of
the writers in the 2000s, Russian literature in Kazakhstan transformed into Russophone
Kazakhstani literature. In this thesis, I argue for the difference between the younger and
older generations of the contemporary Russophone Kazakhstani writers – the latter is
focused on post-traumatic sense of loss and absence, while the former is characterized
by a more positive identification concentrated on the new national post-independent
realities of Kazakhstan..
Practical Implementation of Various Public Key Infrastructure Models
The paper proposes a short comparative analysis of the contemporary models of public key infrastructure (PKI) and the issues of the PKI models real implementation. The Russian model of PKI is presented. Differences between the North American and West Europe models of PKI and Russian model of PKI are described. The problems of creation and main directions of further development and improvement of the Russian PKI and its integration into the global trust environment are defined
To the issue about the purpose and objectives the USA National initiative for cybersecurity education
In the current year, Russia entered a three-year transitional period for the implementation of professional standards designed to replace the traditional regulations of the Unified Qualification Handbook (UQH) for the positions of executives, specialists and employees. Several professional standards have been approved for the field of staffing of information security.
However, from the higher school point of view, the existing variety of approved professional standards can hardly be used as a normative basis for the improvement and development of the existing system of educational standards in the information security area, although such an obvious conceptual task was set in the framework of the transition from UQH to professional standards.
This paper analyses foreign experience in solving this problem using rather impressive example of the United States. A systematic study of the labor (personnel) resources structure in the cybersecurity field was carried on within the framework of the national initiative for cybersecurity education, which is proposed as a fundamental reference resource. That resource can be used to guide the various category users, including educational organizations, to solve their tasks of providing labor resources in the field of cybersecurity.
The cybersecurity workforce framework (CWF) components include such categories as specialty areas, work roles, knowledge, skills, abilities and tasks (performed for any kind of work).
The paper analyzes the presented CWF, its content, as well as its important role in harmonizing the Russian educational standards in the field of cybersecurity