Aleksandar Markovic

A new perspective on the ICT Development Index

Information and Communication Technology (ICT) represents an important structural part of modern society; this is why countries strive for constant progress in ICT and why it draws such significant attention. Bearing this in mind, the main goal of this paper is to present an I-distance methodology that holds a new perspective on the measurement of information development, to compare it to the ICT development index (IDI), and to point out improvements that such methodology provides. IDI combines 11 indicators related to three ICT categories: Access, Use and Skills (by weighting the first two by 40 percent and the third by 20 percent). The approach presented in this study uses the same indicators, synthesizing them into one value. Subsequently, which variables are the most relevant for measuring ICT development level of countries are able to be determined. Consequently, the I-distance method provides useful insight into developing countries and ways that enhance their ranking. The results show that the correlation between the I-distance values and IDI values is very strong, r = 0.961, p < 0.01, which makes I-distance an acceptable measurement method for evaluating countries’ ICT development levels.

Third Harmonic Injection Increasing the Efficiency of High-Power HF Amplifiers

The paper deals with the influence of the third harmonic injection into the grid and anode qirclits of a tuned high power amplifier, in order to improve the efficiency. The linear triode model is used, enabling avaluation of all power balance important parameters in a closed form. The results obtained are compared with the performances of the same amplifiers, without injection.

Increasing the Efficiency of the High-Power Triode HF Amplifier -Why not With the Second Harmonic?

Applying the linear model of the high--power HF triode, the conditions of the optimal design are analyzed in the paper, proposing the injection of the second harmonic in the input and output circuits. The optimal content of the second harmonic is investigated assuming an equal injection of the second harmonic in the input and the output circuits. The results are compared to the similar results of the linear amplifier under the same conditions but without any injection and also with the amplifier with the injection of the third harmonics, previously published.

THE Drive-Wave Shape Influence on the Class C Tuned HF High-Power Amplifiers

The paper investigates the drive-wave shape influence on the performances of tuned HF high-power amplifiers. Using the linear model of high-power HF triode and changing the drive wave shape (cosine, triangular, trapezoidal and pulse) under the same conditions (conducting angle, drive level), the balance of power for the high efficiency design, representing the normalized maximum output power and the efficiency versus the conducting angle or other parameter, are compared.

How the top 500 ARWU can provide a misleading rank

Dear Sir, Every year, academia anxiously awaits the 15 of August, when the official Academic Ranking of World Universities (ARWU) list makes its appearance. This is particularly the case for those universities that want to break into the Top 500 list for the first time. University rankings are very appealing, but the very simplicity of use can be highly misleading in that most rankings are based on a simple formula that aggregates subjectively chosen indicators (Paruolo, Saisana, & Saltelli, 2013; Saisana, D’Hombres, & Saltelli, 2011). Nonetheless, official rankings are quite often used as an indicator of a university’s reputation and performance (Jovanovic, Jeremic, Savic, Bulajic, & Martic, 2012; Docampo, 2013). Accordingly, officials from many universities have been committed to determining which of the ARWU’s six indicators will most likely bring about a much desired Top 500 position. Since the Nobel and Field medal indicators (“Alumni” and “Awards”) may prove far from attainable, as well as the number of highly-cited researchers (HiCi) and number of articles published in Nature and Science (N&S), attention has swiftly turned to the number of articles indexed in the Science Citation Index Expanded and the Social Sciences Citation Index (SCIe and SSCI). Thus, universities—such as The University of Belgrade, hereafter referred to as UB—have introduced much stricter criteria for university professorships (especially concerning the number of papers published in SCIe and SSCI). It would seem that the UB’s results have been immediate: after having 1,650 papers published in 2008 and 1,978 in 2009, 2012 saw a peak result of 3,491 papers published. This resulted in an ARWU Top 301–400 position. With all due respect to the results accomplished, one can debate whether the total number of published papers (without incorporating aspects of quality, such as the impact factor [IF] of the journal) is a proper representation of a university’s scientific output. We gathered data on the UB’s papers published from 2008 to 2012 and the journals (see Table 1) in which the greatest improvement has been noted (the greatest differences in the number of published papers between the years 2008 and 2012) are herein shown. As can be seen, Physical Letters B saw the greatest improvement, with 74 papers published in 2012, in stark contrast to 2008 when only six papers were published. This impressive result is praiseworthy, especially when taking into account the high IF of the journal (4.569). In addition, this conclusion can apply to many other top physics journals (Journal of High Energy Physics and Physical Review Letters, among others). However, the larger number of published papers in 2012 was also the consequence of papers published in the journals Metalurgia International, Technics Technologies Education Management, and HealthMed (all of which have been removed from the Thomson Reuters SCIe list). In addition, the increase in the number of papers published in Serbian journals indexed in the Thomson Reuters SCIe and SSCI list also significantly contributed to the 2012 scientific performance of the UB. In point of fact, among the 582-paper difference for the 14 selected journals, 294 originated from journals removed from the Thomson Reuters SCIe and SSCI list or were journals published in Serbia (accounting for more than 50%). We next looked at several other universities that also placed in the ARWU Top 301–400. The universities selected were those that had a high score for the indicator PUB (the number of articles indexed in the SCIe and SSCI). The key findings are presented in Table 2 concerning the top five journals in which the greatest improvement has been noted (the greatest difference in the number of published papers between the years 2008 and 2012) for each of the universities observed. As can be seen, Sao Paulo State University and the Federal University of Rio de Janeiro have a similar number of published papers in SCIe and SSCI. However, if the journals that saw the greatest increase in the number of published papers for specified universities are examined further, one can easily conclude that the Federal University of Rio de Janeiro published their work in world-leading journals that are accorded a high IF. On the other hand, Sao Paulo State University channeled their scientific contribution to journals with a lower IF than their Rio de Janeiro peers. Very similar findings are obtained when comparing Sichuan and Shandong Universities. When taking all findings into account, it may be concluded that one could easily be distracted by a University’s Top 500 ARWU position and not consider which journals are the underlying reasons for such a ranking. Consequently, it is recommended that the Top 500 universities of the ARWU be more carefully examined for their scientific performance and that more attention be paid to a University’s publishing in world-class journals. In addition, the ARWU methodological framework could be updated to include aspects of journal quality (such as IF) rather than merely quantity (total number of published papers).

MF-AM stereo broadcasting: the choice of modulation

Several AM stereo transmitting systems have been applied to local radio-broadcasting networks on the MF (medium-frequency) band in the US. These systems represent a certain compromise between two mutually contrary requirements: (i) that the broadcast spectrum be at the MF carrier within the determined boundaries (the channel occupancy criterion), and (ii) that the transmitted signal be compatible with MF-AM monaural receivers (the compatibility criterion). It is proved that a transmission system that perfectly satisfies both requirements does not exist. A modulation method called modified compatible quadrature amplitude modulation (MC-QAM) is proposed. The system has simpler circuitry and less distortion, and occupies, under many circumstances, a narrower frequency bandwidth. With slight modifications, existing receivers for C-QAM could be used for MC-QAM. >

First electrochemical investigation of organophosphorus pesticide azametiphos and its quantification using electroanalytical approach

ABSTRACT In this work, the electrochemical behaviour and the subsequent development of an analytical procedure for quantification of pesticide azamethiphos, using boron-doped diamond (BDD) electrode are reported for the first time. It was found that azamethiphos electrochemical behaviour is irreversible oxidation at the potential of around 1.70 V, in 1 M nitric acid (pH 0). Also, it was found that potential of this oxidation was not pH dependent which can be attributed to the no proton involvement in electrochemical reaction on the electrode surface. The square wave voltammetric method was most appropriate for azamethiphos quantification. Under optimised experimental conditions, linear working range from 2 to 100 µM was estimated with the detection limit of 0.45 µM. Negligible effect of the possible interfering compound was observed. The obtained results show that the developed analytical methodology can be an adequate replacement for the, up to date, used methods for detection of organophosphorous pesticide.

Agent-based modelling and simulation in the analysis of customer behaviour on B2C e-commerce sites

This paper examines the development and application of agent-based modelling and simulation in the analysis of customer behaviour on B2C e-commerce websites as well as in the analysis of the effects of various business decisions regarding online sales. The methodology of the agent-based simulation used in this paper may significantly enhance the speed and quality of decision-making in electronic trade. The models developed for this research aim to improve the use of practical tools for the evaluation of the B2C online sales systems in that they allow for an investigation into the outcomes of varied strategies in the e-commerce site management as regards customer behaviour, website visits, scope of sales, income earned, etc. An agent-based simulation model developed for the needs of this research is able to track the interactions of key subjects in online sales: site visitors—prospective consumers, sellers with different business strategies, and suppliers.

Analysis of Interactions of Key Stakeholders on B2C e-Markets - Agent Based Modelling and Simulation Approach

Abstract Background/purpose: This paper discusses the application of ABMS - agent-based modelling and simulation in the analysis of customer behaviour on B2C e-commerce websites as well as in the analysis of various business decisions upon the effects of on-line sales. The continuous development and dynamics in the field of e-commerce requires application of advanced decision-making tools. These tools must be able to process, in a short time period, a large amount of data generated by the e-commerce systems and enable the use of acquired data for making quality business decisions. Methodology: The methodology of the agent-based simulation used in this paper may significantly enhance the speed and quality of decision making in electronic trade. The models developed for the needs of this research aim to improve the use of practical tools for the evaluation of the B2C online sales systems in that they allow for an investigation into the outcomes of varied strategies in the e-commerce site management as regards customer behaviour, website visits, scope of sales, income earned, etc. Results: An agent-based simulation model developed for the needs of this research is able to track the interactions of key subjects in online sales: site visitors - prospective consumers, sellers with different business strategies, and suppliers. Conclusion: Simulation model presented in this paper can be used as a tool to ensure a better insight into the problem of consumer behavior on the Internet. Companies engaged in the B2C e-commerce can use simulation results to better understand their consumers, improve market segmentation and business profitability and test their business policies.

Hardware Topics of an MF-AM Traffic Information Broadcasting Service

Topics related to an Auto-Radio-Information (ARI) Service are considered. As it is well known, such a service is devoted to an instantaneous message distribution to all traffic-participants: at MF-AM and/or VHF-FM via stereo/mono broadcasting services. When using MF-AM transmission this service is automatically identified by two tones located in the subaudio baseband. One of them is the program identification (PI) signal and the other one is the message-in-progress (ME) signal. In order to be compatible to the usual MF-AM stereo/mono broadcasting requirements, a signalization which uses two tones coherent with the stereo pilot-tone is proposed. In the case of the MF-AM mono transmission, the signalization problem is solved by using internally generated (but not transmitted) mythic tones It only serves as a basic signal in the generation process of higher harmonics which are then used as real signalization tones. The application aspects are examined briefly, giving the experimental results and some possible suggestions for future modifications of the MF-AM stereo/mono broadcasting systems, already in use.