Web Service Composition (WSC) is a process that helps to save much programming and cost effort by reusing existing components - web services. This process consists of two major stages - Web Service Discovery and Selection (WSD, WSS). This paper presents an overview of current state-of-the-art WSD and WSS methods. It also provides an analysis and highlighting of major problems like lack of support of the syntactical description in fuzzy logic algorithms in WSD and complex approach shortage in WSS problem. Moreover WSC approach and SLA-Aware WSC System are presented.

Efficiency of DCT-based filters for a wide-class of images is investigated. The study is carried out for additive white Gaussian noise (AWGN) case with several intensity levels. Local DCT-based filter is used as basic denoising technique. Nonlocal BM3D filter known as the state-of-the-art technique for AWGN removal is also exploited. A precise prediction method of denoising efficiency for several quality metrics is proposed. It is shown that statistics of DCT coefficients provides useful information. Regression models for analyzed filters and metrics are presented. The obtained dependence approximations of quality metrics on DCT statistics have high goodness of fit. One-parameter and multi-parameter fitting cases are considered. The most valuable DCT statistics are found.

The boundary problem for eigenmodes in coaxial quad-ridged waveguides has been solved by the transverse field-matching technique. The formulas obtained provide possibilities to calculate cutoff wave numbers and electric and magnetic fields distributions of TEM, TE and TM modes in the presence of the ridges either on the inner or on the outer perfectly conducting cylinder. The analysis of the dependences of cutoff wave numbers and electric field distributions convergences on the number of partial modes has been carried out. It has been shown that for calculation of cutoff wave numbers with residual error less than 0,1 % it is enough to utilize 27 partial modes, and for the correct calculation of fields distributions one should utilize more than 30 partial modes.

The error-correcting capabilities of regular LDPC (Low Density Parity Check) codes and BCH (Bose-Chaudhuri-Hocquenguem) codes are examined. The qualitative analysis and the quantitative assessment of error-correcting abilities are performed for LDPC codes with code word length n = 1000 bits and BCH codes with code word length n = 1023 bits. The code rates of LDPC and BCH codes are determined for a known signal to noise ratio in the gaussian channel; detected code rates are optimal for predefined modulation type and required information reliability on the receiver side.

The directions of efficiency increase of the self-organizing wireless networks MANET are proposed. They consist in the implementation of new methods and radio network management functions, coordination and intellectualization of the methods, corresponding to different OSI-model levels, and also coordination of the network resource management purposes distribution.

In order to satisfy the users' requirements for the productivity and efficiency of tasks implementation the grid-system should implement the effective algorithm of tasks distribution between the computing resources accessible at the moment. The primary purpose of such load balancing in the grid-system is to reduce the time necessary for the user's task implementation. Moreover, it will provide efficient usage of the computing resources and eliminate such a situation that some resources stand idle when the other are overloaded with users' tasks implementation.

In the article the terminology and requirements for safe, reliable operation of critical IT infrastructure were defined. The generalized structure of critical IT infrastructure, by its basic level, sub levels and functionality were described. In the paper for the described structure mathematical model of control of resource allocation in the case of inter-independence processes and universal services were proposed.

The method for assessing a channel capacity and productivity of fiber-optic communication line (FOCL) based on the DWDM (Dense Wavelength Division Multiplexing) technology is proposed. The interrelation between noise-immunity factors and information characteristics of FOCL is highlighted.

The channel utilization factor is a typical QoS functional model of a telecommunication network. A common analytic formula of this factor includes non differentiable members that hinder functional model conversion. This paper introduces an approximation of the QoS functional model based on regression analysis and performed via differentiable functions. Recommendations are given to implement the findings for data flow control in telecommunications.