Vol 13, No 4 (2015)

We present block scheme of complex that provides real-time prediction of satellite communication noise immunity by results of monitoring of mean square small-scale nonhomogeneities deviation of total electron content of ionosphere. Here the output of dual-frequency receiver NovAtel GPStation-6 of satellite radio-navigation system is monitored. According to measured results, we found that regions with unacceptable mean square nonhomogeneities deviation of total electron content are able in mean latitude. Mentioned deviations can lead to great scintillation of receiving signals and unacceptable noise immunity reducing of satellite communication during the 13 minutes. These results can be used for satellite communication system frequency and time parameters adaptation to variations of radio wave transionospheric propagation conditions for noise immunity improvement under ionosphere perturbations like small-scale nonhomogeneities deviation of total electron content

In this work we described and compared a few algorithms for signal correction based on the fast Fourier transform (FFT) and signal correction in frequency domain that was performed by computer techniques and statistical simulation methods. By taking into account two different approaches for packet assembly, we analyzed two different methods for signal correction. First, was nullification method, and second was mean square fault minimization method. The first approach applies passive guard interval, while the second is based on using cyclic prefix. Both methods were realized by software for simulation of wireless channel with required parameters. We present results of researches of signal noise immunity under following conditions: transmission over single-beam channel, transmission over dual-beam channels without both correction, correction based on mean square fault minimization, and correction based on nullification algorithm with unequal beam ratios in noisy channel. We obtained bit-error relations on signal-to-noise ratio under different channel conditions, and present conclusions based on these results.

This article describes prototype of software tool for static analysis of software systems based on a special data set. This data set received from the source code of programs using the open source compiler. The prototype provides to obtain equivalent representation by linear and nonlinear transformations of this data set. The user interface is built by data query language, which syntax provides to set arbitrary combinations of available transformations, and additional parameters correspond to the objectives of the analysis. Conversion options are defined by configuration file being an XML-document. The prototype also provides analysis of the obtained equivalent representations. We descried “temperature” analysis of row syntactic overflow and complexity of source code blocks in the context of control flow by way of example. The prototype was tested on open source library for parsing of XML-documents.

This work is concerned with determination of packet delays inserted by using OpenFlow protocol in virtual computing cluster performed over software defined network by OpenNebula system with installed Floodlight controller. We experimentally found moment characteristics of packet delays. Based on these values we theoretically determined packet delays in channels both with and without OpenFlow via traffic simulation in the kind of queuing system H2/M/1. According to results, packer delay under using OpenFlow protocol is more 1.5 times then under without it. This fact should be taken into account for heavy load software defined network, while we performed experimental research under light load channels.

This work discusses feasibility of dynamic graph visualization method application for e-marketplace model verification. Introduction is concerned with the main research goals and problems. It describes of experiments for data verification and completeness checking. The main part of the article presents detailed description of procedures for verification the results of market environment computing applied for particular enterprise selected for experiment. Here model verification is correctness of transformation from conceptual model to simulation. According to this research, the conceptual model is description of logic of potential interaction between market agents. This work also presents results of performed experiments confirming that developed model corresponds to conceptual model. Authors conclude that e-marketplace environment is a socioeconomic network. We propose arguments to apply dynamic graph visualization for e-marketplace model verification.

В работе рассматривается концепция построения распределенной сети радиосвязи на базе технологии Radio-over-Fiber. Представлен обзор и классификация систем передачи радиосигналов по волоконно-эфирной структуре, методы их реализации. Рассмотрены типовые структурные схемы построения таких систем, их основные компоненты.

This work describes extracting of high quality biometric parameters from stationary image of handwritten signal. At first step, we perform binarization of initial handwritten signal images by Gabor filter and then map the pen movement directions. These maps are divided to segments, and pen movement direction histograms are plot for each segment. Those histograms are used as initial data during training of three-layer neural classifier by backpropagation algorithm. We propose to define high quality biometric parameters corresponding to data from the outputs of the neural classifier second layer. These extracted high quality biometric parameters can be used for training of neural transformer biometry-code according to methods described in the GOST R 52633.

This work presents method for electromagnetic radiation level determination generated by portable computer devices like Notebook. We demonstrated results of experimental measurements performed for the following devices: Notebook Lenovo 15 Inch.; Notebook Samsung 17 Inch. with printer HP LaserJet 1200; Notebook Lenovo 10 Inch.; tablet iPad Apple 10 Inch. on distances 0.5 m and 1.0 under different power supply (external power supply net and internal battery) as well as with and without grounded power supply system. We compared measured results with electromagnetic radiation safety standards ratified in Russia. These data can be applied for environmental monitoring and estimation of computer workstation safety concerned with non-ionizing electromagnetic field radiation.

This work compares features of tree decision algorithms C4.5 and C5.0, which are the most effective data mining classification tool. We considered two software tools: analytics platform Deductor and system See5. Three data sets were tested to improve comparative analysis accuracy. First is conventional Fisher’s iris data set, second contains information about US Congress deputy votes (distribution Deductor), and third includes information about applicants of the one of Russian Federation universities. According to test results, C5.0 builds more compact decision trees, but its operation speed is almost the same to C4.5 under reducing of classification model validity. However, we do not preclude that these results can be explained by using of See5 system demo version that provides only files processing with no more 400 entries.