Vol 14, No 2 (2016)

Voice signal analysis and processing techniques are main directions in the field of voice technologies. Here the frequency analysis is widely used for voice signal processing. Various voice sounds differ by distribution of energy along a frequency axis. At the same time, there is a good reason to consider only frequency bands that possess the main energy of signal division that is so-called information frequency band. We propose to apply method for information frequency band detection based on comparison with adaptively defined threshold. It is clear that additive noise will change energy distribution over frequency domain. This work presents results of researches of information frequency band wrong detection probability value dependence on signal-to-noise ratio. In addition, we present results of comparison between proposed method and method based on energy part setting. Those obtained research results demonstrate the method based on using of adaptive threshold is resistant to additive noise.

Operation of modern special high performance infocommunication networks is able only when all management problems would be solved. Complication of various networks included to infocommunication network leads to extremely complicated procedures of decision making and development of control actions for design of powerful network management automated system. We present rigorous methodological approaches to state and following solution the problem of infocommunication network management that provides to develop algorithmic description for automated management systems. This makes possible to implement long-range automation for special infocommunication network management procedures and to develop special software for automation system complexes.

This work is concerned with features of light confinement and propagation over photonic crystal fibers (PCFs), which are classified on operating principles and geometry. Photonic band gaps and photonic crystals are considered, as well as the most interesting types of PCFs, their structure and applications are overviewed. The present paper deals with application of twisted PCF as a fiber optic wavelength filter that is able to be used for signal transmission at various wavelengths or signal sample transmission at certain wavelength depending on twist parameters. Here light reflection effect in PCF structure is described in terms of geometry optics in the basis of Snell’s law. The work represents overview of temperature influence on filling material condition and thus on refractive index value in PCF structure as well as perspectives of PCF using in various applications of fiber optics and photonics.

Quality of service is the main issue for modern large information systems. Their parameters mostly depend on data sources. Power usage meter reading might be used for billing and data mining analysis, and errors in these time series are undesired. Therefore, effective data cleaning should be performed before necessary data processing. Data quality problems in automatic systems for commercial measurement of power consumption can occur due to various reasons. This work describes classification of those problems, and we propose two-step procedure for cleaning of time series containing errors in automatic systems for commercial measurement of power consumption. The first step applies hierarchical clustering based on Euclidian distance that provides detection the most “unusual” profiles. The second step uses statistical data processing to determine time series outliers. We assume expert makes the final decision. This work is concerned with comparison of two methods for error data detection: SD-method and “Supersmopther” algorithm. We produced comparison for 100 power usage profiles that preliminarily were analyzed by expert.

This work presents mathematical model for call center. It was developed for estimation of probabilistic-temporal parameters influence on call center effectiveness. We derived formulas for determination of mean time for call at the input during primary and repeated call receipt, and formulas for evaluation of control traffic overhead value by primary and repeated calls for the first and second level operators. Derived formulas take into account mean time of post-processing calls. The paper represents plot of call loss probability dependence on service failure intensity due to customer impatience, unacceptable waiting time and repeated calls.

This work presents method for description of operation of digital correct-tor for telecommunication channel amplitude-frequency response and computing of channel parameters. Proposed corrector is based on non-recursive digital filter with unsymmetrical parameters related to filter central parameter. That filter is jointed at the input or output of the channel. Amplitude-frequency response characteristic form is approximated by second order polynomial. Polynomial approximation parameters are evaluated by measurement of channel amplitude-frequency response and following solution of three linear equation system. Filter parameters are computed by formulas been derived from the general expression for Fourier series parameters.

Actually there are many difficulties for solutions of email classification problems. One is the problem of content analysis for two classification groups containing reliable and unreliable data. There are known a number of adaptive and non-adaptive algorithms that should help to solve described problem. Nowadays naive Bayesian classifier algorithm is one of the most popular tool in the field of data classification problem solution. This work is concerned on how to adapt naive Bayesian classifier mechanism for e-mail classification, where e-mails are classified as reliable and unreliable information blocks. We determine naive Bayesian classifier learning process as calculation the probability of one or another word meeting into e-mails.