Vol 16, No 3 (2018)

Traffic in modern multiservice networks is usually correlated, therefore, the methods of classic theory do not work properly. In this paper the results of simulation and comparative analysis of traffic correlation influence for a fractal requests ceiling and requests flow in a case of real multiservice telecommunication networks are given. We examine Pollaczek-Khinchine formula generalization for an average queue length of stationary requests flow with a random correlation as well as opportunities for its application. It’s shown that a real random value of requests number that is proceed at the interval of one request service has an expectation value lesser than 1. It is shown that a process of queueing has passive time intervals that interrupt a correlation link with previous and following process parts. It is shown that correlation dependencies between separate queues values spread only at intervals of employment of queuing network for self-similar processes that have an infinitely big correlation interval.

In queuing theory, the G/G/1 systems are especially relevant in view of the fact that until now there is no solution in the final form for the general case. This article presents the results of queuing systems (QS) G/G/1: system E2/E2/1 with Erlang input distributions of the second order and the system with delay in time. We choose the second-order Erlang distributions as an input for the system considered, which are shifted to the right from the zero point. For such distribution laws, the method of spectral decomposition allows one to obtain a solution in closed form. It is shown that in such a system with delay, the average waiting time of calls in queue is less than in the usual system. Which is explained by the fact that the time shift operation reduces the value of variation coefficients of the intervals between the receipts and the service time, and as it is known from queuing theory, the average requirements waiting time is related to these variation coefficients by a quadratic dependence. The E2/E2/1 system works only for variation coefficients equal to , and the system c allows us to work with the variation coefficients of the arrival and service intervals from the interval (0, ), which extends the scope of these systems. To derive solutions, the classical method of spectral decomposition of the Lindley’s integral equation solution is used.

This article discusses the issues of ensuring the efficiency of the IEEE 802.11 standard network. An orthogonal frequency-division multiplexing channel model is proposed as a function between its basic parameters and the application conditions. The frame transmission time is selected as the main characteristic. Modern enterprise wireless networks require high signal strength as coverage requirements and hence signal strength from the access point cannot be itself a good parameter for data rate selection. Thus, analytical models are obtained for the number of bits in the symbol and the data frame transmission time as a function of the signal to noise ratio for the IEEE 802.11ac standard. The model analysis shows that the error of the model is less than 6% for the most of the data frame size values. The proposed analytical models can be used to assess the effectiveness of the network and, thus, help in the design process of the modern enterprise networks, which require high signal strength for wireless coverage.

The article considers a problem statement of the business process "Construction of prefabricated buildings" simulation modeling. The subject area is described briefly. The relevance of prefabricated constructing lies in the fact that it is associated with the use of effective and economical engineering methods which ensure the conformity of the final product to market requirements. Moreover, in the article some problems are identified that are causing the need for the business process study by modeling. The verbal model and the detailed scheme of the business process are presented. The scheme displays all the operations of the business process and the departments that perform them. Bold arrows show workflows and control flows, thin ones indicate resources used in process, input and output objects. It is proposed to use the Dimov-Maslov method within the confines of statistical simulation modeling. This method combines the virtues of classical statistical approaches and overcomes some of their shortcomings.

Currently, great attention is being paid to making decisions in the field of human resources management of IT organizations. The development and adoption of such decisions are closely related to the processing of information. The higher the effect of the use of personnel information, the more objective decisions will be made by managers on a wide variety of personnel problems. Among the most important problems associated with the use of modern technologies in the information environment of the enterprise, it is necessary to attribute the absence of the necessary theoretical and methodological justification and practical recommendations provided by the latest computer tools in the field of human resource management. Thus, the relevance of the research lies in the need to search for new methods of increasing labor efficiency, including the use of modern information technologies in the field of personnel management.

In the article the authors offer an original model in which audio signals are compressed on the basis of psychoacoustic properties of hearing: namely, sample length and sampling frequency of audio data that the authors refer to in frequency analysis. The necessary conditions are determined, which allow restoring the sound signal quite accurately, after its digital processing and application of frequency discrete orthogonal transformations to the samples of the primary digital signal. The researchers provide recommendations for values of the examined parameters so that compression could be effective, particularly, the conversion interval and the sampling frequency of the audio signal. The calculation for different frequency ranges of audio signals is performed. The ways for further research of the sampling frequency are identified that take into account psychoacoustic peculiarities of human hearing.

The dialectics of the development of organizational and technical control systems under conditions of uncertainty in the solution of emerging problems determine the nature of the laws governing the change in their state. The study of these regularities is of interest for predicting the development and justifying the distribution of resources between the components of the systems. Such issues are especially relevant for organizational and technical systems that do not generate profits, but provide the conditions for its formation. The state of the system cannot be determined without an appropriate classification of states and the principles of their identification. The article establishes the relationship between the cyclical character of the decisions made and the states of organizational and technical control systems.