Serbian energy development based on lignite production

Lignite, as an energy resource, is a mainstay of electricity generation in the Republic of Serbia. Installed capacity of lignite power plants represents 68% of the total installed capacity of Electric Power Industry of Serbia, the only company in Serbia, which manages electricity generation. In the future, with the increase in demand for electricity, both in Serbia and in Europe, we should expect more extensive and effective utilization of lignite as the main energy potential. In addition, due to increased emissions of CO₂, NO_X and other pollutants, the Republic of Serbia must accelerate the implementation of flexible mechanisms of Kyoto Protocol and the guidelines set by the European Union. Lignite in the future will retain its existential importance in the electricity generation in the Republic of Serbia.     

Binding of the hop (Humulus lupulus L.) chalcone xanthohumol to cytosolic proteins in Caco-2 intestinal epithelial cells

Used in the brewing of beer, hops (Humulus lupulus L.) contain the prenylated chalcone xanthohumol, which is under investigation as a cancer chemoprevention agent and as a precursor for the estrogenic flavanones isoxanthohumol and 8-prenylnaringenin. The uptake, transport and accumulation of xanthohumol were studied using the human intestinal epithelial cell line Caco-2 to help understand the poor bioavailability of this chalcone. Studies were carried out using Caco-2 cell monolayers 18-21 days after seeding. The apparent K(m) and V(max) values of xanthohumol accumulation in Caco-2 cells were determined, and the protein binding of xanthohumol in sub-cellular fractions of Caco-2 cells was investigated. Approximately 70% of xanthohumol added to the apical side of Caco-2 cells accumulated inside the cells, while 93% of the intracellular xanthohumol was localized in the cytosol. Xanthohumol accumulation was temperature dependent and saturable with an apparent K(m )value of 26.5 +/- 4.66 muM and an apparent V(max) of 0.215 +/- 0.018 nmol/mg protein/min. Facilitated transport was not responsible for the uptake of xanthohumol, instead, accumulation inside the Caco-2 cells was apparently the result of specific binding to cytosolic proteins. These data suggest that specific binding of xanthohumol to cytosolic proteins in intestinal epithelial cells contributes to the poor oral bioavailability observed previously in vivo.     

UMTS RAN Capacity Analysis for Special Events

Special events such as music festivals, sports etc are characterised as “high user density” where user behaviour is determined by the dynamics of the event. This is the reason that it is necessary for a mobile network operator to dimension its network based on maximum expected resource requirements instead on averaged values. Although special events are taking place almost every week, in most cases not enough attention has been paid to the problem of resource dimensioning in the Universal Mobile Telecommunications System networks, and the appropriate cost function to equate the optimal quantities resources has not been developed. It is therefore necessary to be aware that special events networks should be dimensioned with the maximum resource requirements, using distributed antenna system (DAS) where possible, and the consolidated baseband processing resources. Appropriate cost function will be used to describe optimal design that should depend on the number of sectors needed, radio network controller and the overall network capacity. A suitable radio access network (RAN) analysis has been performed and a cost function has been developed in order to create the metrics that can be used for evaluating the cost of dimensioning the RAN in special events. It can be shown based on proposed metrics that 10 % of savings in resources could be achieved by degrading the grade of service less than 1 %.     

Turbo Coding with Equalization in WCDMA Downlink

In this paper, the performance of turbo coding in WCDMA downlink is considered in conjunction with receivers using two adaptive channel equalizers. Bit error and frame error rates are compared to the performance of the conventional Rake receiver. Special consideration is given to the cases with two receive antennas, the efficiency of the channel interleaver, the number of iterations in decoding, the performance with various numbers of users, the influence of mobile receiver velocity as well as to the effect of power control. The simulation results show that turbo coding, combined with power control and channel equalizers is a very efficient way to implement reliable data transmissions in WCDMA downlink. The results in the paper also verify that the adaptive channel equalizers is a very promising technique to improve the receiver performance and increase the user capacity.     

1D linear-phase band-pass multiplierless FIR Hilbert transformers and filters

An original analytical method, based on modified Christoffel–Darboux formula, is used in the paper in order to synthesise a linear-phase band-pass finite impulse response (FIR) filter function that can have an effect of Hilbert transformer. New structure of the band-pass FIR filter in recursive realisation, together with the corresponding difference equation, is presented providing the efficient filter solution without multipliers. Several examples of filter types for different parity of two real free integer parameters, including a particular solution of Hilbert transformer, are considered in terms of required number of adders and values of cut-off frequencies of the pass and stop bands. A comparison of the proposed band-pass filter characteristics with those of a classical filter solution is provided in the paper.     

An ESD test reduction method for complex devices

We define rules to reduce the ESD test complexity for chips with large pin count. These rules exploit the structural similarity in the pad-ring and have a long history of use without bad experiences. Using these rules an automated software tool can be developed for reduced ESD test generation.     

Study of Dependability Evaluation for Multi‐hierarchical Systems Based on Max–Min Composition

This article presents the model for calculating the performance of dependability for complex technical systems. According to ISO‐IEC 300, dependability is an overall indicator for the quality of service and considers simultaneously reliability, maintainability, and maintenance support. For a proper understanding of the quality of service for any technical system, it is important to define dependability performance at the level of single component as well as at the upper levels—levels of subsystems and entire system. As dependability indicators (reliability, maintainability, and maintenance support) have been defined as linguistic variables, the fuzzy max–min composition has been used for the dependability determination and integration of its indicators. A procedure for the synthesis of single components dependability performance to upper levels in complex technical system is proposed. Max–min composition is again used as a tool for fuzzy synthesis because it enables obtaining the comprehensive and synergetic effect in a process of dependability evaluation. A practical engineering example (mechanical systems at bucket wheel excavator) has been used to demonstrate the proposed dependability synthesis model. Copyright © 2012 John Wiley & Sons, Ltd.     

Dynamics of spatial beams in quaternion description based on the Newmark integration scheme

The rotational quaternions represent a unique four dimensional parametrization of rotations in the three dimensional Euclidean space. In the present paper they are used as the basic rotational parameters in formulating the finite-element approach of geometrically exact beam-like structures. The classical concept of parameterizing the rotation matrix by the rotational vector is completely abandoned so that the only rotational parameters are the rotational quaternions representing both rotations and rotational strains in the beam. The space discretization based on the collocation method is used and the adjustment of the Newmark time-integration algorithm to the quaternion parameterizations of rotation is presented.     

Packet error rate analysis of decode-and-forward free-space optical cooperative networks in the presence of random link blockage

This paper analyses end-to-end packet error rate (PER) of a free-space optical decode-and-forward cooperative network over a gamma–gamma atmospheric turbulence channel in the presence of temporary random link blockage. Closed-form analytical expressions for PER are derived for the cases with and without transmission links being prone to blockage. Two cooperation protocols (denoted as ‘selfish’ and ‘pilot-adaptive’) are presented and compared, where the latter accounts for the presence of blockage and adapts transmission power. The influence of scintillation, link distance, average transmitted signal power, network topology and probability of an uplink and/or internode link being blocked are discussed when the destination applies equal gain combining. The results show that link blockage caused by obstacles can degrade system performance, causing an unavoidable PER floor. The implementation of the pilot-adaptive protocol improves performance when compared to the selfish protocol, diminishing internode link blockage and lowering the PER floor, especially for larger networks.