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In this paper the distribution of world's electricity sources is presented graphically. The contribution of renewable energy sources is focused here. The CO2 emission rate has been discussed from various aspects. A prediction model is presented for world electricity generation capacity, electricity consumption, CO2 emission rate and renewable energy harnessing. At last a brief energy prediction model...
The use of multiple laser transmitters combined with multiple photo detectors has the potential for combating fading effects on turbulent optical channels. In this paper, an analytical approach is presented to evaluate the bit error rate performance of a free space optical link using LDPC coded Q-ary optical PPM over atmospheric turbulence channel. Performance results are evaluated for multiple-laser...
In this paper, we have proposed a novel nanophotonic device for nonlinear applications in the visible range. The proposed device is a photonic crystal fiber nanowire composed of highly transparent silica with a germania doped silica as core material. Numerical analysis has confirmed that the proposed nonlinear device has a maximum Raman gain coefficient of 1324 W-1km-1 with a nonlinearity parameter...
Achieving maximum optical amplifier or repeater spacing in fiber-optic transmission system is compromised by the input power limit due to stimulated Brillouin scattering (SBS). In digital transmission, SBS causes bit error rate degradation. In this paper, we have established analytical model for spectral broadening due to self-phase- and cross-phase modulation and using this broadening, SBS effect...
Energy efficient data transfer is one of the key factors for energy efficient wireless sensor network (WSN). In this paper, an energy efficient cooperative technique is proposed for a WSN where selected numbers of sensors at the transmitting end are used to form a MIMO structure wirelessly connected with selected number of sensors at the receiving end. The selection of nodes in the transmitting end...
Base transit time for an npn SiGe HBT is calculated assuming Gaussian doped base and a generalized trapezoidal Ge profile considering field dependent mobility in excess to doping dependent mobility and diffusivity. Band-gap narrowing (BGN) due to heavy doping, due to presence of Ge and due to change in the density of states (DOS) are also considered. For presence of Ge, a different saturation velocity...
This paper describes the effect of Differential Phase Shift Keying (DPSK) modulation on Four-Wave Mixing (FWM) in a multi-channel, long-haul optical fibre communication system that employs Wavelength Division Multiplexing (WDM). The performance of NRZ-DPSK and the commonly used NRZ-Intensity Modulation with Direct Detection (IMDD) are compared in the presence of FWM, while the factors that influence...
In this paper, a numerical comparison of optical performances of chalcogenide based PCFs with hexagonal and octagonal symmetry has been performed in the mid-IR spectrum for the first time. A tapering factor has been introduced to investigate the effects of core size for both the cases. Qualitative analysis of group velocity dispersion has been presented for a bandwidth of 3500 nm. Later, air filling...
This paper proposes a control methodology for Superconducting Magnetic Energy Storage (SMES) unit, which can significantly decrease the voltage and power fluctuations of grid connected fixed speed wind generators. The SMES system with a voltage-source IGBT converter and two-quadrant DC-DC chopper using IGBT is proposed as a controllable energy storage device. The objective of the proposed SMES control...
An analysis of a GaAs/AlGaAs electrooptic intensity modulator is carried out by using the finite element method. The microwave properties, e.g., the effective index, the characteristic impedance, and the frequency dependent attenuations are calculated using quasi-TEM analysis. The 3-dB optical bandwidth is estimated and it is shown that microwave losses in the dielectric material is an important factor...
An analytical model is developed to determine the 3-D potential distribution of a fully-depleted silicon-on-insulator (SOI) four-gate transistor (G4-FET). The potential variations along the channel and between the junction-gates are assumed to be parabolic due to short channel effect and presence of MOS gates. Using these assumptions and with necessary boundary conditions, the 3-D Poisson's equation...
This paper presents a match-line architecture to reduce the energy consumption of Ternary content-addressable memory (TCAM) and to increase search speed. The proposed match-line (ML) sensing scheme uses a two-step comparison to filter out most of the mismatched MLs in the first step so that the second step comparison is never activated for those mismatched MLs. Simulation using 130-nm 1.2-V CMOS logic...
In conventional grid-connected PV system, the control of real and reactive power is undertaken adjusting both modulation index and phase angle of the inverter. The maximum power point of the PV array is tracked by adjusting duty cycle of the dc-dc converter or modulation index of the inverter. The PWM pattern has to be optimized each time the index of modulation is changed which involves excessive...
This paper presents a modified design of a sliding mode controller based on fuzzy logic for a dc-dc boost converter. Here a proportional - integral (PI)-type current mode control is employed and a sliding mode controller is designed utilizing fuzzy algorithm. Sliding mode controller ensures robustness against all variations and fuzzy logic helps to reduce chattering phenomenon introduced by sliding...
A position sensorless Surface Permanent Magnet Synchronous Motor (SPMSM) drive based on flux angle is presented in this paper. The motor equations are written in rotor fixed d-q reference frame. A PID controller is used to process the speed error to generate the reference torque current keeping the magnetizing current fixed. The estimated stator flux using Recurrent Neural Network (RNN) is used to...
A novel design of a single polarization fiber is proposed in this work. The fiber comprises an elliptical core with a central air-hole and side air holes. Analysis of different polarization properties of the newly designed fiber has been performed both with and without the presence of thermal stress. The investigation shows that the new design has larger birefringence compared to conventional side-hole...
Energy crisis is the most important issue in today's world. Conventional energy resources are not only limited but also the prime culprit for environmental pollution. Renewable energy resources are getting priorities in the whole world to lessen the dependency on conventional resources. Solar energy is rapidly gaining the focus as an important means of expanding renewable energy uses. Solar cells...
Renewable energy based generations are connected at subtransmission and distribution levels and are normally dispersed throughout the network. This causes a number of benefits and challenges for power system operators. This paper outlines voltage and small signal stability issues for a distribution network and provides a number of case studies.
This paper proposes a microcontroller based control method for the maximum power point tracking (MPPT) of a photovoltaic system under variable temperature and insolation conditions. For the reduction of tracking time, fuzzy logic control algorithm is implemented with the embedded microcontroller for improved performance as compared to conventional techniques in power efficiency and swift maximum power...
The effect of temperature and scaling of gate length on the threshold voltage of double gate Ge tunneling FET has been studied. The threshold voltage has been determined from transconductance rather than constant current method. In the 10 nm to 50 nm range scaling has almost no effect on threshold voltage. However, threshold voltage is function of temperature in the range of 250-500 K. Besides, a...
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