SIMPLIFICATION OF HYPERGAMMA DISTRIBUTION FOR CLUSTER PARALLEL WORKLOAD APPROXIMATION
S. V. Gaevoy, W. M. A. Ahmed, S. A. Fomenkov
In this paper computing clusters (CC) are considered. They are used to execute incoming jobs. There is such a CC in our university and we need to predict its service characteristics at executing several workloads. An important method to analyze parallel workloads is modeling execution of those systems by using parallel workload models (PWM). We use PWMs to model the CC in order to get these service characteristics. We have already proposed many PWMs, but all these PWMs use a continuous variable approximation. This approximation can be done either by method of moments (MM), or maximum likelihood method (MLM). The latter gives the more accurate results but consumes much time. The best distributions for the approximation are Hyperexpoential and Hypergamma distributions. It was empirically proved in our and third-party papers. The simplification we have already proposed reduces the time consumption of the Hyperexponential distribution by using MM instead of MLM. In this paper a simplified method of Hypergamma distribution approximation is proposed. It reduces the number of the approximated distribution’s parameters and then uses MM or MLM. Hypergamma distribution is chosen, because it has given the best result among all used distributions including Hyperexponential. Nevertheless the proposed method uses our early proposed simplification for Hyperexponential distribution. To validate the quality of the results described in this paper we use the simulation of this approximation and compare the results with the original workload (from the log) in this paper. The characteristics of the proposed methods are demonstrated. The necessity to select an appropriate approximation method is justified.
Keywords: :Method of Moments, Maximum Likelihood Method, parallel workloads, rigid jobs, simulation, stochastic approximation, Hypergamma distribution.
THE MODELING OF COMPLEX ANTENNA DEVICES ON THE BASIS OF THE APPARATUS OF THE GENERALIZED SCATTERING MATRIX
Y. Shtefanovich, Y. S. Sakharov
Currently, the active development of the telecommunication facilities, used by an increasing number of transmitting and receiving devices can be observed. Between nearby objects in space (antennas, metal-dielectric structures) occurs electrodynamic interactions that affect their work. This paper aims to develop methods for the assessment of the characteristics of this interaction. A leading approach to the study of this problem is the use of a method based on generalized scattering matrix. Knowledge of the generalized scattering matrix provides the possibility for calculations of the characteristics of the antenna system, without considering the geometry. By analogy with the use of matrices of two-and multiprobe used in electrical circuits, generalized scattering matrix is carried out to minimize the calculations for the analysis of complex antenna systems. The paper presents the results of modeling of the interaction loop antenna ball, which is formed of a dielectric material. The dispersion characteristics were calculated based on the method of integral equations. On the basis of calculations of the electrodynamic interaction between objects is possible to estimate the influence of the position of the antennas on the level of measured electromagnetic fields. The materials of the article are of practical value to professionals associated with the design of wireless networks indoors.
Keywords: telecommunication, simulation, scattering of radio waves, scattering matrix, antenna.
THE SIMULATION AND ALGORITHMIC SOLUTIONS OF PROBLEMS IN WIRELESS
COMMUNICATION SYSTEMS IN THE CONDITIONS OF CLOSED SPACES
D. P. Komaritiy, Y. S. Sakharov
The urgency of research is caused by that in modern conditions there is a widespread use of wireless networks. When designing wireless networks, a big role for the modeling stage, which includes the calculations of the basic parameters of wireless access systems. In this regard, this paper aims to identify opportunities to use appropriate approaches in modeling the propagation of radio signals in indoor environments, and at identifying possible errors in calculations. A leading approach to the study of this problem is the use of ray tracing technique, which allows to take into account the different geometry of the premises and materials located within the facilities. The article presents the results of simulation program Wireless InSite. The materials of the paper are of practical value to professionals associated with the design of wireless networks indoors.
Keywords: communication, simulation, wireless networks, algorithm, area.
THE DEVELOPMENT OF OPTIMIZATION SIMULATION MODEL TO SUPPORT THE
PROCESSES OF ORGANIZATION OF TRAVEL SYSTEMS
The development of modern tourism systems determines the need to develop appropriate methods of simulation. This paper examines the task associated with simulation of modern tourism systems. The components of simulation optimization model are described. The peculiarities of discrete-event simulation, continuous simulation, and agent-based are described. In the optimization model includes three basic components: objective function, constraints relating to the model and its variables. It is noted that for the optimization of complex systems effective is the use of genetic algorithms, evolutionary algorithms, search for the prohibition, simulated annealing and hybrid algorithms. The description of the model, which optimizes the work of travel system. The structure of the procedure, allowing the formation of integral evaluation is given.
Keywords: simulation, optimization, tourist organization.
THE ANALYSIS OF ELECTROMAGNETIC WAVE PROPAGATION INSIDE THE BUILDING WITHIN THE RADIAL APPROACH
A. P. Preobrazhensky
In this paper the analysis of the characteristics of radiation methods for the analysis of electromagnetic wave propagation – the method of geometrical optics, physical optics, physical theory of diffraction are considered. In order to determine the amplitude of the field in each point of space is required to determine all the rays that pass through this point. The considered model of distribution of the main beam in the room for two cases – floor reflections and the reflection from the object, located a certain height above the floor. Built according to the horizontal distance to the point of reflection of the beam on the incidence angle, the height of the receiver from the angle of reflection, the height of the receiver for various values of height of the reflecting object.
Keywords: simulation, communication, diffraction, wave propagation in indoor radiation methods.
THE SIMULATION OF SCATTERING CHARACTERISTICS OF OBJECTS HAVING EDGES
A. P. Preobrazhensky
In the paper the problems of scattering of radio waves on the objects, which include edge are considered. First, the analysis of the simplest edges, which is a wedge-shaped structure having a certain angle of solution is given. For the general case the edge of such structures may be truncated. The calculations of the scattering parameters was based on the method of integral equations in the framework of the Kirchhoff approximation. The examples of calculations of scattering characteristics are given, and built the radio image. Further the models of hollow structures is considered. The edges of these hollow structures can be defined by different edges. The calculations of the scattering parameters was based on the method of integral equations. The examples of calculations of scattering characteristics of hollow structures, and built the radio image of the edge part of the hollow structure.
Keywords: simulation, communication, diffraction, wave propagation, design, edge, hollow structure.
THE PERFORMANCE OF THE COMPUTER NETWORK
The paper considers the issues related to the construction of models connected with information propagation in computer networks. The results of research approaches connected with modeling for specific networks are given.
Keywords: simulation, computer network, traffic.
THE PROPOSALS FOR MODIFICATION OF ALGORITHM FOR THE ANALYSIS OF THE SCATTERING CHARACTERISTICS OF OBJECTS
The paper discusses the elements of the algorithm of processing the data when analyz-ing the characteristics of the scattering objects of complex shape.
Keywords: simulation, algorithm, scattering, object.
ABOUT THE FEATURES OF CONSTRUCTION OF THE ALGORITHM FOR DETERMINATION OF THE SPATIAL STRUCTURE OF OBJECTS
In this paper the approaches, which can be useful in assessing the efficiency of tourism are analyzed. Some factors determining influence on the tourist potential of the region are pointed out.
Keywords: marketing, information technology, business.
THE USE OF INFORMATION TECHNOLOGIES AT CREATION OF SYSTEM OF MARKETING CONTROL
In this paper the approaches, which can be useful in assessing the efficiency of tourism are analyzed. Some factors determining influence on the tourist potential of the region are pointed out
Keywords: simulation, tourism, innovation.