In this paper a hybrid modulation scheme based on pulse position modulation (PPM) and binary phase shift keying subcarrier intensity modulation (BPSK-SIM) schemes for free-space optical communications is proposed. The analytical bit error rate (BER) performance is investigated in weak and saturated turbulence channels and results are verified with the simulation data. Results show that performa...

The wind farm layout program FLaP (Farm Layout Program) estimates the wind speed at any point in a wind farm and the power output of the turbines. The ambient flow conditions and the properties of the turbines and the farm are used as input. The core of the program is an axis-symmetric wake model, describing the wake behind one rotor. Here an approach based on the simplified Reynolds equation w...

The analytical formulas for the average intensity and power in the bucket of the relay propagation of partially coherent cosh-Gaussian (ChG) beams in non-Kolmogorov turbulence have been derived based on the extended Huygens-Fresnel principle. The influences of the beam parameters, relay system parameters and the non-Kolmogorov turbulence parameters on relay propagation are investigated by numer...

The propagation of an ON–OFF keying modulated optical signal through an optical atmospheric turbulent channel is considered. The intensity fluctuations of the signal observed at the receiver are modeled using a gamma–gamma distribution. The capacity of this channel is determined for a wide range of turbulence conditions. For a zero inner scale, the capacity decreases monotonically as the turbul...

The performance of Free Space Optical (FSO) systems reduces due to the presence of turbulence and misalignment effects. In this paper, we investigate the error control coding schemes as a candidate solution to mitigate turbulence and misalignment induced fadings over free space optical links. we have investigated for first time the error performance for coded onoff keying (OOK) optical wireless...

Two major performance degrading factors in free space optical communication systems are rainfall and atmospheric turbulence. We study the outage probability and bit-error rate for free-space communication links with spatial diversity and Gaussian-Schell electromagnetism beams over the raining turbulence fading channels by double inverse Gaussian distribution proposed in this paper. Assuming int...

In recent years, there has been a renewed interest in the impact of turbulence on aquatic organisms. In response to this interest, a novel instrument has been constructed, TURBOGEN, that generates turbulence in water volumes up to 13 l. TURBOGEN is fully computer controlled, thus, allowing for a high level of reproducibility and for variations of the intensity and characteristics of turbulence ...

A stochastic-parallel-gradient-descent algorithm (SPGD) based on Zernike polynomials is proposed to generate the phase correction pattern for a distorted orbital angular momentum (OAM) beam. The Zernike-polynomial coefficients for the correction pattern are obtained by monitoring the intensity profile of the distorted OAM beam through an iteration-based feedback loop. We implement this scheme a...

This paper analyses a set of velocity time histories which were obtained at a fixed point in the bottom boundary layer of a tidal stream, 5 m from the seabed, and where the mean flow reached 2.5 m s(-1). Considering two complete tidal cycles near spring tide, the streamwise turbulence intensity during non-slack flow was found to be approximately 12-13%, varying slightly between flood and ebb ti...

Estimation Algorithm for Autonomous Aerial Refueling Using a Vision Based Relative Navigation System. (August 2005) Roshawn Elizabeth Bowers, B.S., Texas A&M University Chair of Advisory Committee: Dr. John Valasek A new impetus to develop autonomous aerial refueling has arisen out of the growing demand to expand the capabilities of unmanned aerial vehicles (UAVs). With autonomous aerial refuel...