According to the signal theory vocal speech presents a non-stationary random process due to time variation of its main characteristics. A special emotional impact is gained during ensemble and choir performances. The article provides the correlation analysis results and the autocorrelation function of ensemble singing calculated, taking into account the non-stationary nature of acoustic signals. The studies have shown that there is a certain visual resemblance between correlation portraits of a non-professional student ensemble and a non-professional solo singer. At the same time the correlation portrait of student and professional co-performance tends to a professional singer correlation portrait. This helps to make a quantitative assessment of an ensemble’s professionalism which, alongside with a vocal teacher’s subjective assessment, can provide an objective view on singers’ voices condition to optimize the academic voice training process in an ensemble, which is important when using this voice assessing method in music schools, colleges and universities.

Keywords: Vocal speech, acoustic signal, ensemble singing, choir performance, non-stationary random process, autocorrelation function, quantitative assessment

Based solutions of avalanche transit diode amplifier for under the influence of microwave amplitude- modulated optical signal at the p-n junction diode is determined by the response of the amplifier , while a detector device characteristic. We investigate the influence of numerous system parameters on product detection.

Keywords: frequency response; avalanche diode; amplifier; detector; Microwave amplitude modulated optical vibration .

The article presents the results of experimental investigations of carbon fabric electrodes for recording electrical biosignals. Experimental studies of carbon fabric electrodes showed good results both in conductivity and usability, for example, for further integration into clothing, that indicates the high quality of carbon fabric electrodes and promising for further uses for cardiac monitoring.

Keywords: Electrodes, carbon fabric, electrical biosignals, cardiac monitoring.

There is an important task to improve timber complex. It is a search of efficient using wood. The research results of energy reserves capacity running on a regularized round timber production technological line for wood construction are given in the article. The research suggests that 40 – 45 percent wood resources using on regularized round timber production technological lines are waste. This capacity can use for manufacturing different energy products: firewood, chip fuel, fuel pellets, fuel briquette. The research made on the plant (limited liability company “Biogrant”) in Karelian Republic.

Keywords: Woodworking, cylindering, technological line, wood costraction, energy reserves, fuelwood, firewood, chip fuel, fuel pellets, briquette

Calculation of coefficient of operating conditions of the pipeline is presented in article for the West Siberian region. Dependence of service life of the pipeline on this coefficient is presented. The data of samples witnesses received in laboratory of nondestructive control, confirming relevance of this subject are provided.

Keywords: corrosion, wall thickness, standard service life, pipeline, coefficient of working conditions, diameter, pressure, settlement resistance.

the problems of moisture (cooling) in the mass-transfer apparatus at different parameters of fluid spray and varying the magnitude of the influence of the electric field in the zone of the spray.

Keywords: heat and mass transfer, mist dispersion, electroaerosol, electrostatic dissipation.

This article discusses the problems of  retail network in Russia and the main directions of development of the domestic networks in connection with the expansion of foreign networks and Russia's WTO accession. In the harsh conditions of competition will survive only those commercial enterprises that will   practically use logistic as business philosophy and methodology, and  the main provisions of logistics management in  their business practice  

Keywords: Retail network, development of retail network, Logistizatcija retail network problems network retail, logistics strategy, logistics management

It is considered questions of automation of the productions, directed on increase of efficiency of the operating enterprises and the organisation of the new enterprises providing decrease of losses of wood resources, expenses of energy and time at all stages industrial forest exploitation. Descriptions of the developed algorithm and a method of automated management are resulted by processes and information streams of the wood enterprises

Keywords: The automated control systems, modelling methods, algorithm, processes industrial forest exploitation

The methods of construction and repair of temporary winter roads, proposed technical solution for creating devices that provide a significant increase in strength, bearing capacity and durability of the repaired snegoledovogo cover winter road at full mechanization of the process of recovery.

Keywords: Winter road, a temporary winter road, moisturizing, repairing, mechanized complex snow mass, milling machine, load capacity

A timber industry complex is a complex of technological processes linked with timber harvesting, wood transport and woodworking. For their optimization are used mathematical and economic methods. The brief overview of the application of mathematical modeling methods for the analysis and optimization of technological processes in the forestry sector is given in the article. Queuing theory is used for analysis of forestry process. For example harvesting technology with the round logs production for wooden construction is considered as G/G/1 queuing system. Well-developed models of queuing theory are recommended for analyzing of forestry process. Simulation models are recommended for deep analysis of forestry process.

Keywords: Forestry process, woodworking, cylindering, queuing theory, timber industry manufacture, wood construction

The paper contains a description of a new method for automatic generation of maps of goods placement. Map of goods placement created by the author's search algorithm. The algorithm is based on ideas of evolutionary search. The proposed algorithm works with a population of constant size, allows not use complex search methods and for a reasonable time find a solution close to the optimum.

Keywords: simulation, evolutionary computation, multicriteria optimization, genetic algorithms

The results of a patent search in the field of quality improvement of main piping valve gate’s sealing faces for the plants of nuclear power, thermal power and oil and gas industries are given

Keywords: valve gate, wedge valve, main piping, patent search, sealing face

The need for specialists who know the basics of engineering creativity and practical skills of invention and the feasibility of using this methodology for functional and technological analysis. The results of the use of the said methodology in Petrozavodsk state University.

Keywords: analysis and synthesis, methodology, technology patentable subject matter

Maximum power pointtracking algorithms are widely used in the solar converters in order to obtain maximum power from the solar array. The article provides a brief description of the work of these algorithms, description of the method of testing based on mathematical modeling using Matlab, Simulink and SimScape packages. The results of modeling and comparative analysis  of the studied algorithms, its  strengths and weaknesses revealed.

Keywords: maximum power point, maximum power point tracker, photovoltaic, buck converter, comparative study of algorithms, perturb and observe method, constant voltage method, constant current method, icremental conductance method

Vocal speech is a random process. Taking into account the fact that the main characteristics of a singing voice vary with time, in the article vocal speech is studied as an acoustic nonstationary random process. To describe this process we should calculate one of its informative parameters – the autocorrelation function. The findings show that there are some differences between the autocorrelation functions for professional and nonprofessional singers. This helps to make a quantitative assessment of a singer’s professionalism which, alongside with a vocal teacher’s subjective assessment, can present an objective view on a singer’s voice and provide a good basis for optimization of academic voice training. Moreover a teacher does not have to be technically educated because this quantitative assessment is presented in diagrams which are quite easy to assess visually. It is especially important to consider when we use the given voice assessing method in music schools, colleges and universities.

Keywords: Vocal speech, acoustic signal, nonstationary random process, autocorrelation function, the maximum autocorrelation interval, quantitative assessment