Multicanonical Monte Carlo modeling of wavelength division multiplexed differential phase shift keying systems

Differential phase shift keying (DPSK) modulation is being considered as a possible candidate for future optical wavelength division multiplexed (WDM) transmission systems. In a single channel link, the balanced interferometric DPSK receiver exhibits increased tolerance against amplified spontaneous emitting (ASE) noise and fiber nonlinear effects. In this paper, a model is presented that can be used to estimate the performance of a multichannel DPSK system taking into account the influence of interchannel phenomena, namely cross-phase modulation (XPM) and four wave mixing (FWM), in the phase noise statistics. The model is based on an approximate solution of the fiber propagation equation and the multicanonical Monte Carlo (MCMC) method. It provides an efficient tool that can be used to investigate the influence of many link design parameters such as channel spacing, launch power, and fiber dispersion. The model is illustrated in the comparison of the performance of multichannel DPSK to on-off keying (OOK) systems. It is verified that, even in the presence of interchannel effects, DPSK modulation greatly enhances the system performance compared to OOK. © 2009 IEEE

Optical delay lines based on soliton propagation in photonic crystal coupled resonator optical waveguides

In this paper, a study of optical delay lines based on soliton propagation in coupled resonator optical waveguides is performed. For a given bit rate and required delay, design equations are given that relate the soliton peak power and collision period to the soliton width. To study the influence of higher order linear and nonlinear dispersion, a continuous wave propagation model incorporating these effects is also derived. Using this model, the soliton stability in the presence of higher order dispersion, optical loss and adjacent soliton pulses is numerically verified. It is also shown that soliton-based delay lines can achieve nanosecond delay at a propagation length of a few millimeters due to the high slow down factors that can be obtained. © 2007 IEEE

Modeling Complex Telecom Investments: A System of Systems Approach

This paper presents a complex telecom investment problem analysis using system of systems concepts. This is necessary due to problem's multidimensional nature with several interdependences, and the presence of uncertainty and competition. A genetic algorithm is implemented in MATLAB in order to optimize the objective function (operator's profitability) of the formulated nonlinear programming problem. This approach is capable of providing optimal policies (regarding, e.g., services pricing, inception of investment, or revenues reinvestment) in a competitive market helping future investors in decision making by using various emulated strategic plans as reference. © 1988-2012 IEEE

Modeling gender evolution and gap in science and technology using ecological dynamics

In this paper a model based on population biology is proposed in order to investigate the evolution of human resources (men and women) in science and technology as a share of labor market as well as the dynamics of their gap. An analytical and a simulation method using the Artificial Bee Colony optimization algorithm are described and used for the determination of the proposed model parameters. The presented model is applied to three case studies; Greece, Portugal and Europe-27.3 The accuracy of the obtained results is confirmed through comparison with actual data. In addition, the model can also be used to accurately forecast future trends. It is illustrated that the gender gap is continuously decreasing, while in the last years, women seem to outperform men in the field of science and technology. The estimation and forecasting ability of the model can be used as an extremely valuable tool for decision and policy makers. © 2012 Elsevier Ltd. All rights reserved

Cost analysis of WDM and TDM fiber-to-the-home (FTTH) networks: A system-of-systems approach

A system-of-systems (SoS) approach for wavelength-division multiplexing (WDM) and time-division multiplexing (TDM) fiber-to-the-home (FTTH) telecommunication networks is presented. Cost evolution curves for individual systems as well for whole FTTH WDM and TDM networks are presented. The analysis can be exploited for a fast and accurate analysis of FTTH deployment costs in dense urban, urban, and suburban areas from the technoeconomic point of view, which is of paramount importance for telecom operators, equipment vendors, regulators, and policy makers. The impact of delaying the deployments or adopting different rollout strategies is also investigated and presented. The SoS emergent behavior is further revealed using exploratory modeling. The results reveal that in all cases, the WDM solution is more expensive than TDM. The total cost for suburban areas is almost six times higher than in dense urban areas and four times than urban areas. © 2012 IEEE

Assessment of the gap and (non-)Internet users evolution based on population biology dynamics

The evolution of Internet and non-Internet users as well as the dynamics of their divide is studied using population biology concepts. Usersevolution and future trends are estimated by applying Lotka-Volterra model. The parameters of the proposed model are determined by both an analytical and a simulation method. The presented model is applied to two cases; Greece and Lithuania. The accuracy of the obtained results is confirmed through actual data. Internet users are constantly increasing while they outperform non-users in the last years. It is confirmed that the maximum growth rate of Internet users in both countries coincides to periods with effective regulation, broadband promotion, provision of bundle products and alternative operatorsinvestments. Models estimation and forecasting ability can be used as a valuable tool for decision and policy makers. Several policy guidelines are provided helping to achieve higher penetration levels. © 2014 Elsevier Ltd