The Influence of SIP Call Control Signalling on VoIP Quality of Experience

The rapid growth in subscribers and usage of multimedia services enlarges the volume of Session Initiation Protocol (SIP) call control signalling creating a need to understand Quality of Experience (QoE) in this case and improve it. This paper provides an analysis of influence of SIP call control signalling on QoE for Voice over Internet Protocol (VoIP) service. The aim was to investigate whether SIP call control signalling load has the influence on the human perception of SIP signalling performances and QoE, and to identify the importance of distinct SIP-based signalling performance metrics. Moreover, the intention was to determine whether SIP call control signalling load changes its impact if previously proposed algorithm for differentiated treatment of SIP messages is activated, and quantify mutual relationships of considered user perceptions and QoE. The findings show that SIP call control signalling load has a strong and negative impact on dependent variables and that the proposed algorithm improves QoE and human perception of SIP signalling performances

Analysis of IPTV Channels Watching Preferences in Bosnia and Herzegovina

IPTV service is a new service which is today offered from almost every Telecom operator. One of the advantages of IPTV service stemming from its architecture is certainly the fact that it is very easy to measure what TV channels are the ones mostly watched. This papers desribes this measurement and analysis results in one Telecom operator in Bosnia and Herzegovina. They describe what TV channels are mostly watched in different time periods. We developed a simple weighting algorithm to order the channels by watching rate. Based on it we are providing extensive tables. This paper forms an industrial contribution with results important for marketing but also is scientific contribution because it introduces one new method of scoring TV channels based on previous measurements in their audience. We also developed IPTV Statistics model and described results from this research for a new statistics model. This paper is the continuous of previously published contributions from this area

GENERALIZED AVERAGED GAUSSIAN QUADRATURE FORMULAS WITH MODIFIED MATRICES

Generalized averaged Gaussian quadrature formulas may yield a smaller error than Gauss quadrature rules. When moments or modified moments are difficult to compute, these formulas can serve as good substitutes. However, generalized averaged Gaussian quadrature formulas may have external nodes, i.e. nodes outside the convex hull of the measure corresponding to the Gauss rules. This would make them unusable when the domain of the integrand is limited to this convex hull. In this paper we investigate whether removing some of the last rows and columns of the matrices determining generalized averaged Gaussian quadrature rules will produce quadrature rules with no external nodes

QUADRATURES WITH MULTIPLE NODES FOR FOURIER-CHEBYSHEV COEFFICIENTS

Gaussian quadrature formulas, relative to the Chebyshev weight functions, with multiple nodes and their optimal extensions for computing the Fourier coefficients in expansions of functions with respect to a system of orthogonal polynomials, are considered. The existence and uniqueness of such quadratures is proved. One of them is a generalization of the well-known Micchelli-Rivlin quadrature formula. The others are new. Numerically stable construction of these quadratures is proposed. By determining the absolute value of the difference between these Gaussian quadratures with multiple nodes for the Fourier-Chebyshev coefficients and their corresponding optimal extensions we get the well-known methods for estimation their error. Numerical results are included. These results are continuation of the recent ones by Bojanov and Petrova (J. Comput. Appl. Math., 2009), and Milovanovi´c and Spalevi´c (Math. Comp., 2014)

Forensic Analysis of Encrypted Volumes Using Hibernation File

Abstract -Nowadays, software tools are commonly used to encrypt data on hard disk. Those tools keep encryption keys in system memory to provide the user easy access to plain text of encrypted files. Key possesion enables data decryption. A procedure that includes usage of hibernation file as a source of memory content is described. Publicly available tools are used to perform the procedure. The procedure is successfully tested on a system that uses current encryption program

Fuzzy adaptive control system of a non-stationary plant with closed-loop passive identifier

Abstract Typically chemical processes have significant nonlinear dynamics, but despite this, industry is conventionally still using PID-based regulatory control systems. Moreover, process units are interconnected, in terms of inlet and outlet material/energy flows, to other neighboring units, thus their dynamic behavior is strongly influenced by these connections and, as a consequence, conventional control systems performance often proves to be poor. This paper proposes a hybrid fuzzy PID control logic, whose tuning parameters are provided in real time. The fuzzy controller tuning is made on the basis of Mamdani controller, also exploiting the results coming from an identification procedure that is carried on when an unmeasured step disturbance of any shape affects the process behavior. In addition, this paper compares a fuzzy logic based PID with PID regulators whose tuning is performed by standard and well-known methods. In some cases the proposed tuning methodology ensures a control performance that is comparable to that guaranteed by simpler and more common tuning methods. However, in case of dynamic changes in the parameters of the controlled system, conventionally tuned PID controllers do not show to be robust enough, thus suggesting that fuzzy logic based PIDs are definitively more reliable and effective

Therapy Culture and Self-Help Culture in Post-Socialist Countries of the Western Balkans – the Neoliberal Transition and New Imaginaries of Subjectivity

The existing research on therapy culture and self-help culture in the countries of the Western Balkans has so far been highly empirically oriented. Therefore, there is a noticeable lack of theoretical conceptualization and historical contextualization in the corpus of available research. By doing a metasynthesis of existing research on therapy culture and self-help culture in the countries of the Western Balkans we aim to develop an appropriate theoretical framework for their future study which would adequately relate these phenomenon to important historical developments in this part of Europe. This theoretical framework will be based on the conceptual apparatus of the “governmentality approach”, adjusted for the study of postsocialist contexts. We will argue that, by using this approach, therapy culture and self-help culture in the Western Balkans can be best understood as a multiplicity of technologies of the self, that are used by citizens as instruments of adjusting their subjectivity in forms of neoliberal governmentality, adopted by their governments since the early 2000s. We will conclude by presenting some advantages and disadvantages of this theoretical framework

Tackling denial of service attacks on key management in software-defined quantum key distribution networks

A QKD network provides an additional security layer for IT-secure cryptographic key distribution that is added to existing conventional networks. Thus, QKD network components must be resilient to security challenges from conventional network environments. This paper provided a novel solution for designing a Key Management System resistant to DoS attacks. Our solution allows applications to function securely in environments with fewer keys. In addition, we have provided approaches for allocating and managing QKD resources to avoid malicious key reservations. Simulation experiments verified the proposed solutions.Web of Science1011052011051

Design and Performance Analysis of a Switched Reluctance Motor Using Finite Element Analysis and Magnetic Equivalent Circuit Model

By being magnet-free, and mechanically robust with a longer constant power range, switched reluctance motor (SRM) is gathering much attention as a potential choice to propel electric vehicles (EVs) and hybrid electric vehicles (HEVs). This paper comprehensively investigates the performance sensitivity to geometric design variables such as rotor diameter, pole arc angles, and yoke thicknesses for an SRM using static two-dimensional (2D) electromagnetic Finite-Element Analysis (FEA). The reason for the change in static characteristics due to variation in reluctance between SRM designs has not been detailed previously. This is addressed by the magnetic equivalent circuit (MEC) model that simplifies the design analysis. Results indicate that stator pole reluctance needs to be given due importance while studying the influence of rotor diameter. Also, it is imperative to set an adequate thickness of the stator and rotor yokes to minimize the effect of saturation on the performance. Rotor diameter and stator pole arc angle have a pronounced influence on the performance while the influence of rotor pole arc angle and yoke thicknesses was relatively less