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An important part of modern science and economics are numerical computations in mathematical
models. Their efficiency depends on the effectiveness of the hardware. This, in turn, is related to
parallel computations’ optimizations. A new approach to the optimizations and developing a tool for
parallel computing process optimization are the goals of the ongoing research. These software tool
development principles and other resulted applications are described in the paper. Properties of computer
architecture are suitable for formalization. Parallel algorithms already exist in a mathematical
form. From the two points, two mathematical models are derived: the model of the computational algorithm
and the computer architecture model. Along with other points, here described their properties
and applications. Both models, even though they represent vastly different real-world objects,
are described in the same terms and with the equivalent level of detail and structure. This distinction
from similar works allows developing a new approach to comparative analysis of the algorithm scalability,
as well as algorithm efficiency for a given architecture. These models are used as a basis for
a core module of the software implementation for simulation and optimizing the architecture and algorithm
interactions. In this article, after the computational process simulation description with the
models’ usage, as a midline working result, placed suggestions for practical using the software, proposed
approach and results of those simulations. At the ending, a few practical examples are demonstrated.
The last simulation example is crosschecked with a computational experiment, derived important
conclusions from its results.
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№ 6(66)
30 december 2016 year
Rubric: Network Technologies Authors: Starchaus I., Keyno P., Khoroshko L., Siluyanov А. |
Abstract: The main line of the article is the proof of the concept of BML language. BML is the
main part of BlockSet methodology created for Web-development. The article examines the problem
of software evaluation on that basis. At beginning of the work authors proposes the new model with
complex of criteria. The criteria includes a lot of properties: psychological factors of developers, the
language features, system requirements and so on. Psychological factors includes perception and training
speed. Language features are flexibility, instructions set, complexity, recipe set. The problem is in
difference between of imperative and declarative programming. There are a few methods of evaluation
by criteria listed above suitable for both language paradigms. The «threshold entry» term introduced
and found correlation between volume and quality of source code. Also authors propose term
of «fault probability» related to the complex of typical project faults appeared during project developing.
In the classification of software metrics authors revealed three main characteristics for evaluation:
work amount, style of code, developer effort. Authors applied the hierarchy analysis method to
identify the most important criterion. Due to research authors proposed «recipe set» block for further
study as fundamental criterion for others.
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The complexity of synchronizing local timers on individual nodes of the communication network
is to assess the time needed for an information message with current time stamp for transporting from
the source to the target node. Transportation time depends on the state of information transmission
channels and routing protocols. To estimate the time advance of the package with time stamp it is proposed
to use a distributed neural network architecture, which contains a delay line with taps, which
changes the information part of the temporary package during its movement through the communication
network. To perform time correction at the delivery of the packet to the target node of the neural
network expert that has the ability to increase the complexity of the internal architecture without
loss of stability of functioning of the cascade-correlation neural network. The learning procedure consists
in tuning only added neuroelements, which makes it possible to increase the speed of operation
of the system as a whole. To improve the efficiency of the entire system has been used a method for
compressing data information part of the temporary package with the use of neural network built on
neuroelement made to a summing integrator with losses on the scheme with switching capacitors. A
complex of two trigonometric neural networks performs data compression by considering the most
significant characteristics of the analyzed signal combinations. Analysis of process of functioning of
the cascade-correlation neural network showed the ability to perform correction of timers located in
the network nodes. Evaluation of the averaged dynamics of change of the error counts time in units
of the communication network proved the effectiveness of the proposed synchronization approach.
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Authentication still remains one of the major problems in information security. There is a large
number of solutions aimed at providing security of authentication. Some of the solutions are intended
to ensure that authentication data are impossible to be compromised by accessing the transfer channel
for authentication data (class A attacks). Other types of security methods protect authentication data in
their storage (class B attacks). Authentication by username and password is currently the most widely
used authentication method. Passwords are stored on a server with implementation of one-way hash
functions. Password hash can be cracked by brute force enumeration, which allows successful class
B attacks. The paper presents a password identification method, which does not involve storing passwords
in one centralized place. Passwords are split in many parts that are stored on separate computers
on the Internet. Assuming that one or several computers of such network are compromised it will not
result in disclosure of any useful authentication data. Hence, remote nodes may be untrusted and all
internet users can become participants of the data exchange. The solution presented in this paper provides
a multiple increase of user password security against class B attacks even should an adversary
succeed in cracking the server and a part of the network nodes. DKAuth is the practical implementation
of the presented technology. The above solutions were tested as an authentication service. The data obtained
evidence that the DKAuth Protocol can be used even in applications with high operation loads.
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№ 6(66)
30 december 2016 year
Rubric: Information security Authors: Bazhayev N., Davydov A., Krivtsova I., Lebedev I., Salakhutdinova K. |
The article сonside the issues of information security specific wireless network architecture. An assessment
of the state of information security systems based on indicators of the events intensity that
occur in the process of malicious impact in terms of queuing theory. The analysis of the potential opportunities
for the offender «soft» attacks on a wireless network. The analytic dependence by which
to measure the state of information security elements of a wireless network architecture. Model of destructive
information impact offender information security. The results showing the accuracy of the
assumptions about the exponential distribution law for the duration of service requests network nodes.
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The development of the methodology of time series analysis has been studied by many researchers.
This G. E. P. Box, G. M. Jenkins, N. N. Taleb, S. Johansen, C. A. Sims, A. Yu. Loskutov,
B. P. Bezruchko, V. B. Bayburin, and many others. One of the effective methods of time series
analysis is the criterion of uniform approximation by Chebyshev, which has not been considered in
the literature in relation to multivalued mappings by using the Hausdorff metric. The paper presents
method of analysis and parameters estimation of a mathematical model of multivalued time
series, composed of ranges of values of a certain indicator using as a criterion of optimality the
maximum of the local Hausdorff distances between ranges of values and the values of the approximating
function.
The aim of this work is to develop a mathematical method of modeling the time series which are
represented by ranges, based on the development of the method of uniform approximation of functions
in case of set-valued maps using the Hausdorff metric, and the creation of effective, from the point of
view of availability of hardware and software implementations in real-time, algorithm.
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